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Primary election competitiveness in state and federal government, 2020

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Last updated on August 5, 2025[1]
2020 State Legislative Competitiveness
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2020 State legislative competitiveness
Annual Report
Open seatsIncumbents in contested primariesMajor party competition
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In 2020, Ballotpedia published state and federal primary election competitiveness data following each state's major-party candidate filing deadline. This includes data from congressional, state legislative, and state executive filings.

The statistics in this report include the percentage of contested partisan primary elections in 2020, the percentage of incumbents who sought re-election, and the percentage of incumbents with a primary challenger.Click here for primary election competitiveness data for the United States.

A contested primary is defined as one in which voters have a choice on the ballot. Most commonly, this means that there is more than one candidate from one party in the race. Exceptions to this include states with multi-member legislative districts and states using atop-two primary system, such asCalifornia andWashington.[2]

Overview

The following statistics are an aggregate of primary election competitiveness data across all states with completed filing deadlines. Corresponding data from 2014 and 2016 are provided for comparative purposes.

  • In 2020, an average of 2.3 candidates per seat filed for election compared to 2018 when 2.4 candidates per seat ran. In 2016, 2.2 candidates per seat ran, and in 2014, 2.1 candidates per seat ran on the ballot.
  • 15.0% of seats were open.[3] Comparing to previous cycles, 20.0% of seats were open in 2018, 17.4% in 2016, and 16.9% in 2014.
  • 20.5% of possible primary races were contested in 2020. Comparatively, 23.2% of primaries were contested in 2018, 19.1% in 2016, and 18.2% in 2014.
  • 22.7% of incumbents had contested primaries. In 2018, 24.9% of incumbents had a primary opponent. In 2016 and 2014, respectively, 22.8% and 21.7% of incumbents had contested primaries.

In general, congressional elections had more contested primaries, followed by statewide executive races. The further down-ballot a race is, the less likely it was to be contested.

The table below shows cumulative primary competitiveness and incumbency statistics by office. You may need to move the table horizontally using the scrollbar at the bottom of the table depending on your screen size.

2020 aggregate primary competitiveness data
OfficeTotal seatsOpen seatsTotal candidatesDemocratic primaries contestedRepublican primaries contestedTop-two primaries contestedTotal contestedIncumbents contested in primariesTotal incumbents contested in primaries
U.S. Senate3342422222169.2%1553.6%
U.S. House435412,0521982006358.1%19850.3%
State executives1444951036432139.1%3536.5%
State legislature5,87587612,35383688210917.0%1,00620.1%
Totals6,48797015,1571,0921,14719420.5%1,25422.7%


The below tables contain the same aggregate information for the previous years.

2018

2018 aggregate primary competitiveness data
OfficeTotal seatsOpen seatsTotal candidatesDemocratic primaries contestedRepublican primaries contestedTop-two primaries contestedTotal contestedIncumbents contested in primariesTotal incumbents contested in primaries
U.S. Senate3332491429270.3%1550.0%
U.S. House435602,0152411705558.5%19050.8%
State executives2641001,029961062145.5%6740.4%
State legislature[4]6,0651,19413,2971,0051,01110719.3%1,08222.2%
Totals6,7971,35716,5901,3561,31618523.2%1,35424.9%

2016

2016 aggregate primary competitiveness data
OfficeTotal seatsOpen seatsTotal candidatesDemocratic primaries contestedRepublican primaries contestedTop-two primaries contestedTotal contestedIncumbents contested in primariesTotal incumbents contested in primaries
U.S. Senate3652662022365.2%1858.1%
U.S. House435451,5881331705544.8%19650.4%
State executives91423002829938.8%2039.2%
State legislature[5]5,9161,03211,91875294010816.6%98520.2%
Totals6,4781,12414,0729331,16117519.1%1,21922.8%

2014

2014 aggregate primary competitiveness data
OfficeTotal seatsOpen seatsTotal candidatesDemocratic primaries contestedRepublican primaries contestedTop-two primaries contestedTotal contestedIncumbents contested in primariesTotal incumbents contested in primaries
U.S. Senate3161911523163.9%1456.0%
U.S. House435431,4711191615341.7%16742.6%
State executives211687287179838.3%5136.4%
State legislature[6]6,0511,01912,0466469589415.5%98319.5%
Totals6,7281,13614,4368511,22115618.2%1,21521.7%

Breakdown by office

U.S. Senate



U.S. House


State executive


State legislative


See also

Footnotes

  1. The numbers reflected here are subject to change by the time of the general election. Additionally, Ballotpedia is currently conducting a decade-wide audit of all state legislative elections in order to standardized data from previous years.
  2. In the case of top-two or nonpartisan primaries, all candidates are included in the total number of candidates regardless of their party affiliation.
  3. This analysis defines a seat as open if the incumbent did not file to run for re-election or filed to run for re-election but withdrew before the primary filing deadline.
  4. State legislative elections in Nebraska's nonpartisan Senate were not included in this analysis.
  5. State legislative elections in Nebraska's nonpartisan Senate were not included in this analysis.
  6. State legislative elections in Nebraska's nonpartisan Senate were not included in this analysis.
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