Margin of victory analysis for the 2018 state legislative elections

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2018 Elections
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On November 6, 2018, 87 of the nation's 99 state legislative chambers held regularly-scheduled elections for 6,073 seats, meaning that nearly 82% of all state legislative seats were up for election.

Democrats gained control of 309 seats and six chambers, while losing majority control of one chamber. Republicans lost control of 295 seats and six chambers while entering into a power-sharing agreement in one chamber where they had previously been in the minority. Minor-party and independent candidates lost 14 seats.[1]

Across all 6,073 seats up for election, the average margin of victory was 25.8%. An electoral margin of victory (MOV) is the difference between the share of votes cast for the winning candidate and the second-place candidate in an election.

Eighty-eight state legislative races were decided by margins of 0.5% or less in 2018. This figure includes two races—Alaska House of Representatives District 1 and Kentucky House of Representatives District 13—which were decided by a single vote. They were among 16 races decided by 10 votes or fewer.

HIGHLIGHTS
  • Major-party candidates won 1,078 seats by margins of 10% or less; 573 of those seats were won by Republicans and 505 by Democrats.
  • The average margin of victory was 26.8% for Democrats and 22.3% for Republicans.
  • The chamber with the smallest average margin of victory in 2018 was the South Dakota House of Representatives (7.7%), followed by the New Hampshire House of Representatives (8.0%), and the North Dakota House of Representatives (9.6%). All three chambers use multimember districts.

    • On this page, you will find an overview of average margins of victory by chamber, a detailed breakdown of each legislative chamber's margins of victory, and a closer look at the 88 races decided by margins of 0.5% or smaller.

    Margin of victory

    The margin of victory is the difference between the vote share received by a winning candidate and the runner-up. For example, if Candidate A wins an election with 55 percent of the vote and Candidate B, the second-place finisher, wins 45 percent of the vote, the winner's margin of victory is 10 percent. In chambers with multimember districts, the margin of victory is calculated as the difference between the winning candidate with the fewest votes and the losing candidate with the most votes. Margins of victory can be used to measure electoral competitiveness, political party or candidate strength, and, indirectly, the popularity of a particular policy or set of policies.

    Upper chamber average margins of victory

    The map below shows the average margin of victory in each state legislative upper chamber that held elections in 2018. A darker shade of blue indicates a larger average margin of victory. The largest average margin of victory was 51.6% in Tennessee and the smallest was 10.3% in Vermont. Hover over a state to view the average margin of victory. States in grey did not hold regularly-scheduled elections for any seats in their upper chamber in 2018.

    The table below shows the number of seats up for election and the average margin of victory in each state legislative upper chamber.

    Lower chamber average margins of victory

    The map below shows the average margin of victory in each state legislative lower chamber that held elections in 2018. A darker shade of blue indicates a larger average margin of victory.The largest average margin of victory was 38.7% in Alabama and the smallest was 7.7% in South Dakota. Hover over a state to view the average margin of victory. States in grey did not hold regularly-scheduled elections for any seats in their lower chamber in 2018.[2]

    The table below shows the number of seats up for election and the average margin of victory in each state legislative lower chamber.

    Election results by chamber

    The chart below displays the breakdown of races by the winner's partisan affiliation and margin of victory for each state legislative chamber with single-member districts which held elections in 2018. A darker shade of red or blue indicates a larger margin for that party. The table below displays how many seats were up for election in each chamber and how many seats each party won. It also includes a breakdown of how many seats Democrats and Republicans won by 10% or less and without opposition in each chamber, as well as the average margin of victory for each party. Click on a particular header to sort the table.

    Average MOV for state legislative elections, 2018
    Chamber Seats up for election Democratic Party Seats won by Democrats Democratic Party Seats won by Democrats by margins of 10% or less Democratic Party Seats won by unopposed Democrats Democratic Party Average margin of victory for Democrats Republican Party Seats won by Republicans Republican Party Seats won by Republicans by margins of 10% or less Republican Party Seats won by unopposed Republicans Republican Party Average margin of victory for Republicans Grey.png Seats won by independent and minor party candidates
    Alabama State Senate
    35
    8
    0
    6
    45.9%
    27
    2
    12
    28.9%
    0
    Alabama House of Representatives
    105
    28
    1
    21
    41%
    77
    3
    32
    36.5%
    0
    Alaska State Senate
    10
    4
    1
    1
    15.4%
    6
    0
    2
    26.4%
    0
    Alaska House of Representatives
    40
    16
    6
    1
    17.8%
    23
    5
    3
    25%
    1
    Arizona State Senate
    30
    13
    0
    6
    26.5%
    17
    5
    0
    17.6%
    0
    Arizona House of Representatives
    31
    15
    7
    3
    11.1%
    16
    9
    0
    8.7%
    0
    Arkansas State Senate
    18
    5
    0
    3
    23.9%
    13
    0
    5
    38.4%
    0
    Arkansas House of Representatives
    100
    24
    1
    14
    27.1%
    76
    6
    41
    30.7%
    0
    California State Senate
    20
    14
    3
    1
    30.7%
    6
    3
    0
    12.4%
    0
    California State Assembly
    80
    60
    7
    4
    37.4%
    20
    5
    0
    15.7%
    0
    Colorado State Senate
    17
    9
    0
    0
    29.1%
    8
    2
    0
    25.5%
    0
    Colorado House of Representatives
    65
    41
    5
    5
    27.6%
    24
    3
    0
    25.1%
    0
    Connecticut State Senate
    36
    23
    8
    1
    25.3%
    13
    7
    0
    10.2%
    0
    Connecticut House of Representatives
    151
    92
    20
    13
    33.9%
    59
    22
    5
    15.8%
    0
    Delaware State Senate
    10
    6
    1
    2
    27.6%
    4
    1
    0
    19%
    0
    Delaware House of Representatives
    41
    26
    1
    9
    36.8%
    15
    2
    4
    19.7%
    0
    Florida State Senate
    22
    7
    2
    5
    3.6%
    15
    7
    0
    18%
    0
    Florida House of Representatives
    120
    47
    9
    29
    20.6%
    73
    18
    8
    19.3%
    0
    Georgia State Senate
    56
    21
    2
    15
    38%
    35
    3
    18
    28.2%
    0
    Georgia House of Representatives
    179
    75
    12
    52
    16.7%
    104
    12
    58
    29.7%
    0
    Hawaii State Senate
    13
    12
    0
    5
    42.6%
    1
    1
    0
    0.9%
    0
    Hawaii House of Representatives
    51
    46
    1
    31
    38.6%
    5
    1
    1
    27.8%
    0
    Idaho State Senate
    35
    7
    0
    1
    27.8%
    28
    1
    13
    34.8%
    0
    Idaho House of Representatives
    70
    14
    3
    2
    21.1%
    56
    2
    28
    31.7%
    0
    Illinois State Senate
    39
    24
    4
    14
    17.1%
    15
    5
    6
    14.4%
    0
    Illinois House of Representatives
    118
    74
    9
    42
    19.7%
    44
    10
    12
    17.2%
    0
    Indiana State Senate
    25
    4
    1
    0
    17.1%
    21
    2
    6
    23.5%
    0
    Indiana House of Representatives
    100
    33
    5
    21
    15.7%
    67
    6
    10
    29.9%
    0
    Iowa State Senate
    25
    12
    3
    4
    30.4%
    13
    5
    2
    15.1%
    0
    Iowa House of Representatives
    100
    46
    8
    18
    25%
    54
    12
    5
    21.1%
    0
    Kansas House of Representatives
    125
    40
    7
    23
    18.6%
    85
    13
    37
    24.5%
    0
    Kentucky State Senate
    19
    2
    0
    1
    15.5%
    17
    6
    1
    19.2%
    0
    Kentucky House of Representatives
    100
    39
    12
    7
    22.8%
    61
    10
    8
    24.8%
    0
    Maine State Senate
    35
    21
    3
    2
    22.7%
    14
    4
    0
    17.4%
    0
    Maine House of Representatives
    151
    89
    19
    9
    24.5%
    57
    16
    6
    17.6%
    5
    Maryland State Senate
    47
    32
    3
    10
    49.4%
    15
    4
    1
    22.1%
    0
    Maryland House of Delegates
    70
    44
    9
    10
    16.3%
    26
    10
    2
    16.8%
    0
    Massachusetts State Senate
    40
    34
    2
    23
    26.8%
    6
    2
    2
    12.2%
    0
    Massachusetts House of Representatives
    160
    127
    4
    92
    31.8%
    32
    7
    11
    17.1%
    1
    Michigan State Senate
    38
    16
    3
    0
    35.1%
    22
    3
    0
    17.7%
    0
    Michigan House of Representatives
    110
    52
    8
    0
    40.8%
    58
    7
    0
    21%
    0
    Minnesota House of Representatives
    134
    75
    16
    2
    31.6%
    59
    8
    0
    22.7%
    0
    Missouri State Senate
    17
    3
    0
    1
    38.9%
    14
    3
    0
    32.8%
    0
    Missouri House of Representatives
    163
    47
    3
    22
    38.5%
    116
    7
    18
    33.1%
    0
    Montana State Senate
    25
    11
    4
    2
    14.7%
    14
    3
    2
    30.7%
    0
    Montana House of Representatives
    100
    42
    6
    16
    22.5%
    58
    7
    10
    32.6%
    0
    Nebraska State Senate
    24
    3
    0
    2
    46.3%
    10
    1
    3
    28.1%
    11
    Nevada State Senate
    11
    6
    1
    1
    27.6%
    5
    1
    0
    20.6%
    0
    Nevada State Assembly
    42
    29
    6
    10
    19.3%
    13
    2
    3
    23.6%
    0
    New Hampshire State Senate
    24
    14
    6
    1
    17.2%
    10
    5
    0
    10.6%
    0
    New Hampshire House of Representatives
    224
    146
    84
    19
    10.3%
    78
    67
    4
    4.6%
    0
    New Mexico House of Representatives
    70
    46
    7
    23
    19.3%
    24
    7
    11
    18.9%
    0
    New York State Senate
    63
    40
    8
    10
    47%
    23
    7
    6
    16.1%
    0
    New York State Assembly
    150
    106
    5
    41
    55.2%
    43
    8
    7
    22.3%
    1
    North Carolina State Senate
    50
    21
    5
    0
    31.6%
    29
    5
    0
    23%
    0
    North Carolina House of Representatives
    120
    55
    15
    1
    32.4%
    65
    9
    0
    25.8%
    0
    North Dakota State Senate
    24
    6
    3
    1
    15.7%
    18
    2
    3
    29.1%
    0
    North Dakota House of Representatives
    27
    7
    5
    1
    5.2%
    20
    9
    3
    12.3%
    0
    Ohio State Senate
    17
    7
    1
    0
    44.7%
    10
    4
    0
    20.3%
    0
    Ohio House of Representatives
    99
    38
    7
    8
    31%
    61
    5
    0
    28.7%
    0
    Oklahoma State Senate
    24
    7
    1
    3
    29.4%
    17
    1
    2
    30%
    0
    Oklahoma House of Representatives
    101
    25
    5
    12
    12.6%
    76
    11
    16
    24.5%
    0
    Oregon State Senate
    17
    11
    0
    3
    26.8%
    6
    3
    0
    16.4%
    0
    Oregon House of Representatives
    60
    38
    9
    11
    28%
    22
    2
    3
    26.8%
    0
    Pennsylvania State Senate
    25
    12
    5
    5
    17.1%
    13
    3
    0
    23.6%
    0
    Pennsylvania House of Representatives
    203
    93
    11
    53
    27.9%
    110
    20
    19
    24.8%
    0
    Rhode Island State Senate
    38
    33
    2
    16
    28%
    5
    2
    1
    8.3%
    0
    Rhode Island House of Representatives
    75
    66
    8
    37
    25.6%
    9
    3
    2
    13.6%
    0
    South Carolina House of Representatives
    124
    44
    2
    26
    43.5%
    80
    3
    42
    31.2%
    0
    South Dakota State Senate
    35
    5
    2
    2
    9.5%
    30
    3
    1
    28.3%
    0
    South Dakota House of Representatives
    44
    10
    7
    3
    1.9%
    34
    19
    0
    11.2%
    0
    Tennessee State Senate
    18
    4
    0
    2
    71%
    14
    1
    3
    32.2%
    0
    Tennessee House of Representatives
    99
    26
    2
    15
    31%
    73
    3
    8
    40.2%
    0
    Texas State Senate
    15
    5
    2
    1
    22.9%
    10
    3
    0
    26.1%
    0
    Texas House of Representatives
    150
    67
    10
    30
    35.2%
    83
    17
    17
    31.6%
    0
    Utah State Senate
    15
    5
    0
    0
    35.8%
    10
    1
    1
    39.4%
    0
    Utah House of Representatives
    75
    16
    1
    1
    33.2%
    59
    8
    6
    38.6%
    0
    Vermont State Senate
    17
    11
    4
    2
    14.5%
    4
    2
    2
    4.5%
    2
    Vermont House of Representatives
    118
    72
    22
    34
    12.8%
    35
    15
    9
    9.7%
    11
    Washington State Senate
    25
    17
    4
    0
    32.7%
    8
    2
    1
    20.2%
    0
    Washington House of Representatives
    98
    57
    8
    13
    32.8%
    41
    11
    1
    17.7%
    0
    West Virginia State Senate
    17
    8
    6
    0
    7.9%
    9
    2
    0
    20.7%
    0
    West Virginia House of Delegates
    74
    28
    17
    5
    9.1%
    46
    15
    2
    18.9%
    0
    Wisconsin State Senate
    17
    6
    2
    2
    18.2%
    11
    4
    2
    13.8%
    0
    Wisconsin State Assembly
    99
    36
    1
    27
    36.6%
    63
    10
    6
    19.6%
    0
    Wyoming State Senate
    15
    2
    0
    1
    24.7%
    13
    1
    8
    29.3%
    0
    Wyoming House of Representatives
    60
    9
    2
    3
    15%
    50
    6
    30
    26.1%
    1
    Total
    5679
    2717
    505
    974
    26.8%
    2929
    573
    591
    22.3%
    33

    State legislative races decided by 0.5% or less

    In 2018, there were 88 races decided by margins of 0.5% or smaller. New Hampshire had 18 such races, three times as many as second-place Kentucky and West Virginia. The following table lists each race. In races which took place in multimember districts, only the last-place winner and the first-place runner-up are listed.

    State legislative races decided by 0.5% or less, 2018
    District Winner Runner-up Margin (%) Margin (number of votes)
    Alaska House of Representatives District 1
    Republican Party Bart Lebon
    Democratic Party Kathryn Dodge
    0%
    1
    Kentucky House of Representatives District 13
    Democratic Party James Glenn Jr.
    Republican Party D.J. Johnson
    0%
    1
    New Hampshire House of Representatives Belknap 3
    Republican Party Richard Beaudoin
    Democratic Party Gail Ober
    0%
    2
    New Hampshire House of Representatives Coos 4
    Republican Party Kevin Craig
    Democratic Party Herb Richardson
    0.3%
    4
    Kentucky House of Representatives District 96
    Democratic Party Kathy Hinkle
    Republican Party Jill York
    0%
    5
    Idaho State Senate District 15
    Republican Party Fred Martin
    Democratic Party Jim Bratnober
    0%
    6
    Kentucky House of Representatives District 27
    Republican Party Nancy Tate
    Democratic Party Jeff Greer
    0%
    6
    New Hampshire House of Representatives Hillsborough 26
    Democratic Party Brett Hall
    Republican Party John Lewicke
    0.1%
    6
    New Hampshire House of Representatives Merrimack 8
    Republican Party Robert Forsythe
    Democratic Party Edward Cherian
    0.5%
    6
    Kentucky House of Representatives District 91
    Democratic Party Cluster Howard
    Republican Party Toby Herald
    0%
    7
    New Hampshire House of Representatives Sullivan 8
    Republican Party Thomas Laware
    Democratic Party John Streeter
    0.4%
    7
    Minnesota House of Representatives District 5A
    Democratic Party John Persell
    Republican Party Matt Bliss
    0%
    8
    New Hampshire House of Representatives Hillsborough 5
    Democratic Party Donna Mombourquette
    Republican Party Gerald Griffin
    0.1%
    8
    Iowa House of Representatives District 55
    Republican Party Michael Bergan
    Democratic Party Kayla Koether
    0.1%
    9
    New Hampshire House of Representatives Hillsborough 6
    Republican Party Joe Alexander Jr.
    Republican Party Jeffrey Day
    0%
    9
    South Dakota House of Representatives District 27
    Republican Party Steve Livermont
    Democratic Party Margaret Ross
    0.1%
    10
    Pennsylvania House of Representatives District 49
    Republican Party Bud Cook
    Democratic Party Steven Toprani
    0.1%
    11
    Connecticut House of Representatives District 120
    Democratic Party Philip Young
    Republican Party Jim Feehan
    0.1%
    13
    New Hampshire House of Representatives Hillsborough 22
    Republican Party Reed Panasiti
    Democratic Party Daniel Veilleux
    0.1%
    13
    Montana House of Representatives District 22
    Republican Party Lola Sheldon-Galloway
    Democratic Party Laura Dever
    0.4%
    14
    Montana House of Representatives District 51
    Republican Party Frank Fleming
    Democratic Party Darryl Wilson
    0.4%
    15
    Maine House of Representatives District 82
    Grey.png Kent Ackley
    Republican Party Randall Greenwood
    0.4%
    16
    Connecticut House of Representatives District 101
    Republican Party Noreen Kokoruda
    Democratic Party John-Michael Parker
    0.1%
    18
    New Hampshire House of Representatives Merrimack 3
    Democratic Party Joyce Fulweiler
    Republican Party Kathleen Lauer-Rago
    0.4%
    18
    North Dakota State Senate District 25
    Republican Party Larry Luick
    Democratic Party Perry Miller
    0.3%
    21
    Kentucky House of Representatives District 81
    Republican Party Deanna Frazier
    Democratic Party Morgan Eaves
    0.1%
    24
    Nevada State Senate District 20
    Republican Party Keith Pickard
    Democratic Party Julie Pazina
    0%
    24
    New Hampshire House of Representatives Sullivan 6
    Republican Party John Callum
    Democratic Party Virginia Irwin
    0.5%
    24
    New Mexico House of Representatives District 63
    Republican Party Martin Ruben Zamora
    Democratic Party George Dodge Jr.
    0.5%
    27
    South Dakota State Senate District 12
    Republican Party R. Blake Curd
    Democratic Party Kasey Olivier
    0.3%
    27
    Vermont House of Representatives Grand Isle-Chittenden District
    Republican Party Leland Morgan
    Republican Party Michael Morgan
    0.4%
    28
    New Hampshire House of Representatives Hillsborough 2
    Republican Party J.P. Marzullo
    Democratic Party Aaron Gill
    0.3%
    29
    Rhode Island House of Representatives District 28
    Republican Party George Nardone
    Democratic Party Lucas Murray
    0.5%
    31
    Florida House of Representatives District 89
    Republican Party Mike Caruso
    Democratic Party Jim Bonfiglio
    0%
    32
    Kansas House of Representatives District 111
    Republican Party Barbara Wasinger
    Democratic Party Eber Phelps
    0.4%
    35
    North Dakota House of Representatives District 43
    Democratic Party Matt Eidson
    Republican Party Ben Olson
    0.4%
    35
    Iowa House of Representatives District 82
    Republican Party Jeff Shipley
    Democratic Party Phil Miller
    0.3%
    37
    New Hampshire House of Representatives Belknap 9
    Democratic Party Charlie St. Clair
    Republican Party Steven Whalley
    0.4%
    37
    Oklahoma House of Representatives District 62
    Republican Party Daniel Pae
    Democratic Party Larry Bush
    0.5%
    42
    Illinois House of Representatives District 54
    Republican Party Thomas R. Morrison
    Democratic Party Maggie Trevor
    0.1%
    43
    Washington State Senate District 42
    Republican Party Doug Ericksen
    Democratic Party Pinky Vargas
    0.1%
    46
    Texas House of Representatives District 138
    Republican Party Dwayne Bohac
    Democratic Party Adam Milasincic
    0.1%
    47
    Kentucky House of Representatives District 88
    Democratic Party Cherlynn Stevenson
    Republican Party William Farmer Jr.
    0.2%
    48
    Connecticut House of Representatives District 30
    Democratic Party Joe Aresimowicz
    Republican Party Michael Gagliardi
    0.4%
    50
    New Hampshire House of Representatives Rockingham 5
    Democratic Party Anne Warner
    Republican Party Roger Fillio
    0.1%
    51
    Ohio House of Representatives District 28
    Democratic Party Jessica Miranda
    Republican Party Jonathan Dever
    0.1%
    56
    New Hampshire House of Representatives Hillsborough 7
    Republican Party Linda Camarota
    Republican Party Bart Fromuth
    0.1%
    59
    Florida House of Representatives District 26
    Republican Party Elizabeth Fetterhoff
    Democratic Party Patrick Henry
    0.1%
    61
    West Virginia House of Delegates District 36
    Democratic Party Amanda Estep-Burton
    Republican Party Chris Pritt
    0.1%
    62
    South Dakota House of Representatives District 9
    Democratic Party Michael Saba
    Republican Party Michael Clark
    0.4%
    67
    North Carolina House of Representatives District 103
    Democratic Party Rachel Hunt
    Republican Party William Brawley
    0.2%
    68
    New Hampshire House of Representatives Hillsborough 21
    Democratic Party Kathryn Stack
    Democratic Party Brenda Grady
    0.1%
    70
    West Virginia House of Delegates District 32
    Democratic Party Margaret Staggers
    Republican Party Austin Haynes
    0.2%
    70
    West Virginia House of Delegates District 50
    Democratic Party Michael Angelucci
    Republican Party Guy Ward
    0.2%
    72
    Pennsylvania State Senate District 6
    Republican Party Robert Tomlinson
    Democratic Party Tina Davis
    0.1%
    74
    New Hampshire House of Representatives Rockingham 6
    Republican Party Stephen Pearson
    Democratic Party Michelle Sawyer-Moge
    0.1%
    76
    South Dakota House of Representatives District 13
    Democratic Party Kelly Sullivan
    Republican Party Rex Rolfing
    0.5%
    80
    Washington House of Representatives District 42-Position 1
    Republican Party Luanne Van Werven
    Democratic Party Justin Boneau
    0.1%
    81
    Indiana House of Representatives District 15
    Democratic Party Chris Chyung
    Republican Party Harold Slager
    0.3%
    82
    Connecticut State Senate District 33
    Democratic Party Norm Needleman
    Republican Party Melissa Ziobron
    0.2%
    85
    Connecticut State Senate District 17
    Republican Party George Logan
    Democratic Party Jorge Cabrera
    0.2%
    85
    Missouri House of Representatives District 14
    Democratic Party Matt Sain
    Republican Party Kevin Corlew
    0.5%
    85
    South Dakota House of Representatives District 25
    Republican Party Tom Pischke
    Democratic Party Dan Ahlers
    0.5%
    98
    Washington State Senate District 26
    Democratic Party Emily Randall
    Republican Party Marty McClendon
    0.1%
    104
    New Hampshire State Senate District 23
    Democratic Party Jon Morgan
    Republican Party William Gannon
    0.4%
    105
    West Virginia House of Delegates District 13
    Republican Party Scott Cadle
    Democratic Party Scott Brewer
    0.5%
    108
    New Hampshire House of Representatives Merrimack 24
    Republican Party Dick Marple
    Democratic Party Kathleen Martins
    0.5%
    113
    Texas House of Representatives District 132
    Democratic Party Gina Calanni
    Republican Party Mike Schofield
    0.2%
    113
    Minnesota House of Representatives District 47B
    Republican Party Greg Boe
    Democratic Party Donzel Leggett
    0.5%
    117
    Nevada State Assembly District 4
    Democratic Party Connie Munk
    Republican Party Richard McArthur
    0.4%
    120
    Nevada State Assembly District 37
    Democratic Party Shea Backus
    Republican Party Jim Marchant
    0.5%
    135
    Ohio House of Representatives District 43
    Republican Party Jeffrey Todd Smith
    Democratic Party Dan Foley
    0.3%
    137
    Wisconsin State Assembly District 14
    Democratic Party Robyn Vining
    Republican Party Matt Adamczyk
    0.4%
    138
    Maryland House of Delegates District 34A
    Democratic Party Steve Johnson
    Republican Party Glen Glass
    0.4%
    165
    West Virginia State Senate District 8
    Democratic Party Richard Lindsay
    Republican Party Ed Gaunch
    0.5%
    165
    Maryland House of Delegates District 33
    Democratic Party Heather Bagnall
    Republican Party Tony McConkey
    0.1%
    185
    Maryland State Senate District 34
    Republican Party Bob Cassilly
    Democratic Party Mary-Dulany James
    0.4%
    189
    Oregon State Senate District 26
    Republican Party Chuck Thomsen
    Democratic Party Chrissy Reitz
    0.4%
    209
    Texas House of Representatives District 108
    Republican Party Morgan Meyer
    Democratic Party Joanna Cattanach
    0.3%
    220
    Michigan House of Representatives District 19
    Democratic Party Laurie Pohutsky
    Republican Party Brian Meakin
    0.5%
    224
    North Carolina State Senate District 9
    Democratic Party Harper Peterson
    Republican Party Michael V. Lee
    0.3%
    231
    Arizona State Senate District 28
    Republican Party Kate Brophy McGee
    Democratic Party Christine Marsh
    0.3%
    267
    West Virginia House of Delegates District 48
    Republican Party Terry Waxman
    Democratic Party Richard Iaquinta
    0.4%
    292
    Florida State Senate District 18
    Democratic Party Janet Cruz
    Republican Party Dana Young
    0.2%
    411
    Maryland House of Delegates District 8
    Republican Party Joseph Boteler III
    Democratic Party Carl Jackson
    0.5%
    570
    Arizona House of Representatives District 6
    Republican Party Bob Thorpe
    Democratic Party Felicia French
    0.3%
    577
    California State Assembly District 77
    Republican Party Brian Maienschein
    Democratic Party Sunday Gover
    0.3%
    607
    Ohio State Senate District 3
    Democratic Party Tina Maharath
    Republican Party Anne Gonzales
    0.5%
    705

    Seats up again in 2020

    Of the 5,679 state legislative districts in which elections were held in 2018, 4,798 held elections again in 2020. The average margin of victory across these districts in 2018 was smaller than the national average at 24.9%. Republicans won seats in 2,454 of these districts while Democrats won seats in 2,375.[4] The average margin of victory in districts with a Democratic winner was 27.8%, while the average margin of victory for districts with a Republican winner was 24.5%.

    Among chambers with districts up for election again in 2020, the smallest average margin of victory in 2018 was 7.7% in the South Dakota House of Representatives while the largest was 37.3% in the South Carolina House of Representatives. Among only districts with Democratic winners, the chamber with the smallest average margin of victory was the South Dakota House of Representatives at 1.9% while the largest was 55.2% in the New York State Assembly. Among Republican winners, the smallest average margin of victory was 4.5% in the Vermont State Senate and the largest was 40.2% in the Tennessee House of Representatives.

    The following table lists all 55 state legislative chambers which held regularly-scheduled elections for the same seats in 2020 as in 2018. The number of districts with seats up in both years and the average margin of victory in 2018 is included for each chamber. Also included is the number of districts with Democratic and Republican winners and the average margins of victory for those districts.

    2018 Margins of victory for state legislative seats up in 2018 and 2020
    Chamber Seats up Average MoV Seats won by a Democrat in 2018 Average Democratic MoV in 2018 Seats won by a Republican in 2018 Average Republican MoV in 2018
    Alaska House of Representatives
    40
    21.2%
    16
    17.8%
    23
    25%
    Arizona House of Representatives
    30
    10.1%
    15
    11.1%
    16
    8.7%
    Arizona State Senate
    30
    22%
    13
    26.5%
    17
    17.6%
    Arkansas House of Representatives
    100
    28.9%
    24
    27.1%
    76
    30.7%
    Arkansas State Senate
    18
    31.1%
    5
    23.9%
    13
    38.4%
    California State Assembly
    80
    26.5%
    60
    37.4%
    20
    15.7%
    Colorado House of Representatives
    65
    26.3%
    41
    27.6%
    24
    25.1%
    Connecticut House of Representatives
    151
    24.9%
    92
    33.9%
    59
    15.8%
    Connecticut State Senate
    36
    17.8%
    23
    25.3%
    13
    10.2%
    Delaware House of Representatives
    41
    28.3%
    26
    36.8%
    15
    19.7%
    Florida House of Representatives
    120
    20%
    47
    20.6%
    73
    19.3%
    Georgia House of Representatives
    179
    23.2%
    75
    16.7%
    104
    29.7%
    Georgia State Senate
    56
    33.1%
    21
    38%
    35
    28.2%
    Hawaii House of Representatives
    51
    33.2%
    46
    38.6%
    5
    27.8%
    Idaho House of Representatives
    70
    26.4%
    14
    21.1%
    56
    31.7%
    Idaho State Senate
    35
    31.3%
    7
    27.8%
    28
    34.8%
    Illinois House of Representatives
    118
    18.5%
    74
    19.7%
    44
    17.2%
    Indiana House of Representatives
    100
    22.8%
    33
    15.7%
    67
    29.9%
    Iowa House of Representatives
    100
    23.1%
    46
    25%
    54
    21.1%
    Kansas House of Representatives
    125
    21.6%
    40
    18.6%
    85
    24.5%
    Kentucky House of Representatives
    100
    23.8%
    39
    22.8%
    61
    24.8%
    Maine House of Representatives
    151
    16.1%
    89
    24.5%
    57
    17.6%
    Maine State Senate
    35
    20.1%
    21
    22.7%
    14
    17.4%
    Massachusetts House of Representatives
    160
    29.8%
    127
    31.8%
    32
    17.1%
    Massachusetts State Senate
    40
    19.5%
    34
    26.8%
    6
    12.2%
    Michigan House of Representatives
    110
    30.9%
    52
    40.8%
    58
    21%
    Minnesota House of Representatives
    134
    27.1%
    75
    31.6%
    59
    22.7%
    Missouri House of Representatives
    163
    35.8%
    47
    38.5%
    116
    33.1%
    Montana House of Representatives
    100
    27.6%
    42
    22.5%
    58
    32.6%
    Nevada State Assembly
    42
    21.5%
    29
    19.3%
    13
    23.6%
    New Hampshire House of Representatives
    204
    8%
    146
    10.3%
    78
    4.6%
    New Hampshire State Senate
    24
    13.9%
    14
    17.2%
    10
    10.6%
    New Mexico House of Representatives
    70
    19.1%
    46
    19.3%
    24
    18.9%
    New York State Assembly
    150
    33.5%
    106
    55.2%
    43
    22.3%
    New York State Senate
    63
    31.5%
    40
    47%
    23
    16.1%
    North Carolina House of Representatives
    120
    29.1%
    55
    32.4%
    65
    25.8%
    North Carolina State Senate
    50
    27.3%
    21
    31.6%
    29
    23%
    Ohio House of Representatives
    99
    29.8%
    38
    31%
    61
    28.7%
    Oklahoma House of Representatives
    101
    18.5%
    25
    12.6%
    76
    24.5%
    Oregon House of Representatives
    60
    27.4%
    38
    28%
    22
    26.8%
    Pennsylvania House of Representatives
    203
    26.3%
    93
    27.9%
    110
    24.8%
    Rhode Island House of Representatives
    75
    19.6%
    66
    25.6%
    9
    13.6%
    Rhode Island State Senate
    38
    18.2%
    33
    28%
    5
    8.3%
    South Carolina House of Representatives
    124
    37.3%
    44
    43.5%
    80
    31.2%
    South Dakota House of Representatives
    37
    7.7%
    10
    1.9%
    34
    11.2%
    South Dakota State Senate
    35
    18.9%
    5
    9.5%
    30
    28.3%
    Tennessee House of Representatives
    99
    35.6%
    26
    31%
    73
    40.2%
    Texas House of Representatives
    150
    33.4%
    67
    35.2%
    83
    31.6%
    Utah House of Representatives
    75
    35.9%
    16
    33.2%
    59
    38.6%
    Vermont House of Representatives
    104
    13%
    72
    12.8%
    35
    9.7%
    Vermont State Senate
    13
    10.3%
    11
    14.5%
    4
    4.5%
    Washington House of Representatives
    98
    25.2%
    57
    32.8%
    41
    17.7%
    West Virginia House of Delegates
    67
    15.2%
    28
    9.1%
    46
    18.9%
    Wisconsin State Assembly
    99
    28.1%
    36
    36.6%
    63
    19.6%
    Wyoming House of Representatives
    60
    17.5%
    9
    15%
    50
    26.1%
    Overall
    4798
    24.9%
    2375
    27.8%
    2454
    24.5%

    2018 state legislative election analysis

    See also: State legislative elections, 2018

    Heading into the 2018 elections, Republicans held a majority of state legislative chambers. As of November 2017, 67 chambers were under GOP control, while Democrats held majorities in 32 chambers.[5]

    The following table details partisan balance in all 99 chambers.

    Partisan Control of All 99 State Legislatures
    Pre-election Post-election
    Legislative Chamber Democratic Party Republican Party Democratic Party Republican Party Split Democratic Party Republican Party
    State senates 14 36 18 (+4) 32 (-4) 0
    State houses 18 31 19 (+1) 29 (-2) 1
    Total: 32 67 37 (+5) 61 (-6) 1

    The following table details partisan balance of all 7,383 state legislative seats.

    Partisan Balance of All 7,383 State Legislative Seats
    Pre-election Post-election
    Legislative Chamber Democratic Party Republican Party Other[6] Democratic Party Republican Party Other[6]
    State senates 809 1,135 28 869 1,076 27
    State houses 2,314 2,986 111 2,574 2,781 56
    Total: 3,123 4,121 139 3,443 3,857 83


    Democrats had a net gain of 308 seats in the 87 state legislative chambers that held regularly-scheduled elections on November 6, 2018. Republicans lost 294 seats in the elections, and third-party and independent candidates lost 14 seats.

    Democrats gained 65 state senate seats. Republicans lost 60 Senate seats, and third-party and independent candidates lost five.

    Democrats gained 243 state house seats. Republicans lost 234 state house seats, and third-party and independent candidates lost nine.

    The charts below show the total changes in state legislative seats, state senate seats, and state house seats, respectively.

    Change in state legislative partisan composition, 2018 elections
    Total Before After Net
    Democrats Democratic Party 2,815 3,123 +308
    Republicans Republican Party 3,757 3,463 -294
    Other/3rd parties Grey.png 38 24 -14
    Total 6,561 6,561 --


    Change in state senate partisan composition, 2018 elections
    Total Before After Net
    Democrats Democratic Party 651 716 +65
    Republicans Republican Party 947 887 -60
    Other/3rd parties Grey.png 8 3 -5
    Total 1,606 1,606 --


    Change in state house partisan composition, 2018 elections
    Total Before After Net
    Democrats Democratic Party 2,164 2,407 +243
    Republicans Republican Party 2,810 2,576 -234
    Other/3rd parties Grey.png 30 21 -9
    Total 5,004 5,004 --

    Flipped seats

    See also: State legislative seats that changed party control, 2018

    The map below contains a state-by-state breakdown of state legislative seats that changed party control in the November 2018 elections. Hover over a state to view how many seats each party flipped.


    Battleground chambers

    Ballotpedia tracked 22 state legislative battleground chambers in 2018.

    Heading into the 2018 elections, Democrats controlled 10 battleground chambers and Republicans controlled 12 battleground chambers.[7]

    Democrats captured six Republican-held battleground chambers in the election—the Colorado State Senate, Maine State Senate, Minnesota House of Representatives, New Hampshire House of Representatives, New Hampshire State Senate, and New York State Senate.

    Republicans did not capture any Democratic battleground chambers, but they did enter into a power-sharing agreement in the Alaska House of Representatives, which was previously controlled by Democrats.

    Battlegrounds were chambers that we anticipated would be, overall, more competitive than other chambers and have the potential to see significant shifts in party control in the 2018 general elections.

    Criteria for identification as a battleground chamber included the majority party's share of seats, the number of competitive races, and more. Read the complete list of criteria here.

    These were the 22 battleground chambers in 2018.

    Democratic Party Alaska House of Representatives (Power-sharing between parties)
    Republican Party Arizona State Senate
    Democratic Party Colorado House of Representatives
    Republican Party Colorado State Senate (Democratic gain)
    Democratic Party Connecticut House of Representatives
    Democratic Party Connecticut State Senate
    Democratic Party Delaware State Senate
    Republican Party Florida State Senate
    Republican Party Iowa House of Representatives
    Democratic Party Maine House of Representatives
    Republican Party Maine State Senate (Democratic gain)
    Republican Party Michigan House of Representatives
    Republican Party Michigan State Senate
    Republican Party Minnesota House of Representatives (Democratic gain)
    Democratic Party Nevada State Senate
    Republican Party New Hampshire House of Representatives (Democratic gain)
    Republican Party New Hampshire State Senate (Democratic gain)
    Democratic Party New Mexico House of Representatives elections
    Republican Party New York State Senate (Democratic gain)
    Democratic Party Washington House of Representatives
    Democratic Party Washington State Senate
    Republican Party Wisconsin State Senate




    The columns in the chart below list the following information:

    • Seats up in 2018: This was the number of seats in the chamber that were up for election in 2018.
    • Margin: This was the difference in seats between the majority and minority parties.
    • Majority share of seats: This was the percentage of the chamber's total seats controlled by the majority party.
    • Last time party control changed?: This was the election where the party in power before the 2018 elections took control of the chamber.
    2018 battleground chambers
    Chamber Seats up in 2018 Margin Majority share of seats Last time party control changed? Did it flip?
    Alaska House of Representatives* All 40 D+4 55 percent 2016 Power-sharing agreement
    Arizona State Senate 17 of 30 R+4 56.7 percent 2002 No
    Colorado House of Representatives All 65 D+7 55.4 percent 2012 No
    Colorado State Senate 17 of 35 R+2 51.4 percent 2014 Yes Democratic Party
    Connecticut House of Representatives All 151 D+9 53.0 percent 1986 No
    Connecticut State Senate** All 36 D+0 50 percent 1996 No
    Delaware State Senate 10 of 21 D+1 52.4 percent 1974 No
    Florida State Senate 22 of 40 R+6 55.0 percent 1994 No
    Iowa House of Representatives All 100 R+17 58.0 percent 2010 No
    Maine House of Representatives All 151 D+3 48.3 percent 2012 No
    Maine State Senate All 35 R+1 51.4 percent 2014 Yes Democratic Party
    Minnesota House of Representatives All 134 R+21 57.5 percent 2014 Yes Democratic Party
    Michigan House of Representatives All 110 R+17 57.3 percent 2010 No
    Michigan State Senate All 38 R+17 71.1 percent 1982[8] No
    Nevada State Senate 11 of 21 D+2 47.6 percent 2016 No
    New Hampshire House of Representatives All 400 R+45 53.0 percent 2014 Yes Democratic Party
    New Hampshire State Senate All 24 R+4 58.3 percent 2010 Yes Democratic Party
    New Mexico House of Representatives All 70 D+7 54.3 percent 2016 No
    New York State Senate* All 63 R+1 50.8 percent 2010 Yes Democratic Party
    Washington House of Representatives All 98 D+2 51.0 percent 1998 No
    Washington State Senate 24 of 49 D+1 51.0 percent 2012 No
    Wisconsin State Senate 18 of 33 R+3 54.5 percent 2010 No

    *This chamber were controlled by a minority party coalition because some members of the party with the numerical majority caucus with the minority party.
    ** This chamber was evenly divided 18-18 following the 2016 elections. Democrats maintained an effective majority because Lieutenant Gov. Nancy Wyman (D) could cast tie-breaking votes.


    See also

    Footnotes

    1. ↑ This figure does not include the Nebraska State Senate, which held nonpartisan elections.
    2. ↑ Nebraska does not have a state legislative lower chamber.
    3. ↑ In chambers with multimember districts, this refers to the number of districts up for election, since margin of victory is calculated per district.
    4. ↑ Some of these districts were multimember districts where a Democrat and a Republican won.
    5. ↑ Although the Nebraska State Senate elects its members in nonpartisan elections, members of the chamber generally function along party lines when it comes to voting and caucusing. Please see Nebraska State Senate partisan affiliation for more information.
    6. ↑ 6.0 6.1 Third party incumbents and vacancies.
    7. ↑ Two chambers — the Alaska House of Representatives and the New York State Senate — were controlled by minority coalitions, giving effective control of the chamber to the party with a numerical minority.
    8. ↑ Detroit News, "Democrats in Michigan seek to flip state House in 2018," July 8, 2018
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