Congressional margin of victory analyses, 2012-present

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Congressional Analysis Archive
Margins of victory
Congressional margin of victory analyses Congressional elections decided by 10 percentage points or fewer Minor-party candidates who won more than the margin of victory
Incumbents
U.S. Congress incumbents who did not run for re-election Incumbents defeated in congressional elections Incumbent win rates by state Results of federal elected officials seeking other offices
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New members elected in congressional elections U.S. House elections without a Democratic or Republican candidate States with both gubernatorial and U.S. Senate elections • Comparison of state delegations to Congress
2024 Election Analysis Hub

Between 2012 and 2024, the average margin of victory for U.S. Senate races was 19.4%, and the average margin of victory for U.S. House races was 31.4%.

This overview page compiles margin-of-victory (MOV) data from U.S. Senate and U.S. House elections from 2012 to 2024. On this page, you will find overview figures as well as highlights from and links to each previous analysis.

An electoral margin of victory is the difference between the share of votes cast for the winning candidate and the second-place candidate in an election. 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. 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.

The table below shows the average margins of victory for House and Senate races since 2012. Click on an average margin to read a summary of that year's analysis.

Average MOV for Congressional elections, 2012-2024
Chamber	2012	2014	2016	2018	2020	2022	2024
U.S. Senate	20.0%	22.6%	22.1%	16.8%	18.1%	19.6%	16.9%
U.S. House	31.9%	35.8%	36.6%	30.2%	28.8%	28.9%	27.3%

2024

See also: Election results, 2024: Congressional margin of victory analysis

The narrowest elections in both chambers were decided by margins under one percentage point. The narrowest U.S. Senate election in 2024 was for the open seat Michigan. Elissa Slotkin (D) defeated Mike Rogers (R) by a margin of 0.34 percentage points (48.6% to 48.3%). The narrowest U.S. House election in 2024 was for California's 13th Congressional District, where Adam Gray (D) defeated incumbent Rep. John Duarte (R) by a margin of 0.09 percentage points, or 187 votes out of more than 200,000 votes cast.

HIGHLIGHTS

The average MOV across 353 U.S. Senate elections was 16.9 percentage points, the second-narrowest average since we started collecting this data in 2012.

The average MOV across 435 U.S. House elections was 27.3 percentage points, the narrowest average since we started collecting this data in 2012.

Republicans had a larger average MOV than Democrats in U.S. Senate elections (14.4 percentage points versus 20.2 percentage points) and U.S. House elections (27.9 percentage points to 26.8 percentage points).

Click here for margins of victory for all regularly scheduled Congressional elections held in 2024.

2022

See also: Election results, 2022: Congressional margin of victory analysis

The closest elections in both chambers were decided by margins under one percentage point. The closest U.S. Senate election in 2022 was the United States Senate election in Nevada. Incumbent Catherine Cortez Masto (D) defeated Adam Laxalt (R) by a margin of 0.78 percentage points. The closest U.S. House election was in Colorado's 3rd Congressional District, where Lauren Boebert (R) defeated Adam Frisch (D) by a margin of 0.17 percentage points, or 546 votes out of more than 300,000 votes cast. Boebert's margin was 540 votes more than the closest race in 2020. In that race, Mariannette Miller-Meeks (R) defeated Rita Hart (D) by a margin of 6 votes out of nearly 400,000 cast, the narrowest margin of victory in any U.S. House election since 1984.

HIGHLIGHTS

The average MOV across 35 U.S. Senate elections was 19.6 percentage points, larger than the 18.1 percentage points average in 2020 Senate elections.

The average MOV across 435 U.S. House elections was 28.9 percentage points, up slightly from 28.8 percentage points in 2020, and the second smallest average MOV since 2012.

Republicans had a larger average MOV than Democrats in Senate races (22.9 percentage points versus 16.7 percentage points) and House races (29.3 percentage points to 28.4 percentage points).

Click here for margins of victory for all regularly scheduled Congressional elections held in 2022.

2020

See also: Election results, 2020: Congressional margin of victory analysis

The closest elections in both chambers were decided by margins under 2 percentage points. The closest U.S. Senate election in 2020 was the regularly-scheduled Senate election in Georgia. Jon Ossoff (D) defeated incumbent David Perdue (R) by a margin of 1.23 percentage points in the January 5, 2021, runoff. In the U.S. House, Mariannette Miller-Meeks (R) won election to the open seat in Iowa's 2nd Congressional District by a margin of six votes over Rita Hart (D), the narrowest margin in any U.S. House election since 1984.

HIGHLIGHTS

The average MOV across 35 U.S. Senate elections was 18.1%, larger than the 16.8% average in 2018 Senate elections but smaller than the average MOV in any other year since 2012.

The average MOV across 435 U.S. House elections was 28.8%, the smallest since at least 2012.

Republicans had a larger average MOV in Senate races (22.0% versus 12.9%), while Democrats had a larger average MOV in House races (31.5% versus 26.0%)

Click here for margins of victory for all regularly scheduled Congressional elections held in 2020.

2018

See also: Margin of victory analysis for the 2018 congressional elections

The closest election in each chamber was decided by a margin smaller than 0.2 percentage points. The closest U.S. Senate election was Gov. Rick Scott's (R-Fla.) defeat of incumbent Bill Nelson (D) by a margin of 0.12 percentage points. In Georgia's 7th congressional district, incumbent Rob Woodall (R) defeated Carolyn Bourdeaux (D) by a margin of 0.15 percentage points. The U.S. House race in North Carolina's 9th congressional district, which was not certified, was excluded from this analysis.

HIGHLIGHTS

The average MOV in 33 regularly-scheduled U.S. Senate races was 16.8 percentage points.

The average MOV in U.S. House elections was 30.2 percentage points.

Democrats recorded larger average margins of victory than Republicans, particularly in House races, where a 13.8 percentage point margin separated the parties' averages.

Click here for margins of victory for all regularly scheduled Congressional elections held in 2018.

2016

See also: Margin of victory analysis for the 2016 U.S Senate elections

See also: Margin of victory analysis for the 2016 U.S House elections

U.S Senate

HIGHLIGHTS

The average margin of victory was 22.1 percent. This is very close to the average of 22.6 percent in 2014.

The average margin of victory in battleground races was 5.37%.

The average MOV for Republican winners was 22.13 percent, while Democratic winners averaged a MOV of 22.06 percent.

The closest race was in New Hampshire, where challenger Maggie Hassan (D) defeated incumbent Kelly Ayotte (R) by 0.1 percent of the vote.

Click here to read more about margins of victory in the 2016 U.S. Senate elections.

U.S. House

HIGHLIGHTS

The average margin of victory was 36.6 percent. This is larger than the average of 35.8 percent in 2014.

The average margin of victory in battleground races was 5.71 percent.

On average, Republicans won by smaller margins than Democrats. The average MOV for Democratic winners was 41.54 percent, while Republican winners averaged a MOV of 33.51 percent.

The closest race was in California's 49th Congressional District, where incumbent Darrell Issa (R) defeated Douglas Applegate (D) by 0.5 percent of the vote.

Click here to read more about margins of victory in the 2016 U.S. House elections.

2014

See also: Margin of victory analysis for the 2014 congressional elections

U.S. Senate

HIGHLIGHTS

U.S. Senate races had an average margin of victory of 22.6 percent in 2014, higher than the average margin in 2012 of 20 percent.

The average margin for Democratic winners was 18.7 percent, while the average margin for Republican winners was 24.7 percent.

The closest Senate race in 2014 was in Virginia, where incumbent Mark Warner (D) defeated Ed Gillespie (R) by a margin of 0.8 percent.

Click here to read more about margins of victory in the 2014 U.S. Senate elections.

U.S. House

HIGHLIGHTS

The average margin of victory in U.S House elections was 35.8 percent in 2014, higher than the average margin in 2012 of 31.8 percent.

Democratic winners had an average margin of 36.9 percent, and Republican winners had an average margin of victory of 35 percent.

The closest House race in 2014 was in Arizona's 2nd Congressional District, where Martha McSally (R) defeated incumbent Ron Barber (D).

Click here to read more about margins of victory in the 2014 U.S. House elections.

2012

See also: Margin of victory analysis for the 2012 U.S Senate elections

See also: Margin of victory analysis for the 2012 U.S House elections

U.S. Senate

HIGHLIGHTS

The average margin of victory was 20 percent.

The smallest margin of victory was in North Dakota, where Heidi Heitkamp (D) defeated Rick Berg (R) by 0.9 percent.

The largest margin of victory was in Wyoming, where John Barrasso (R) defeated Tim Chesnut (D) by 54.1%.

Click here to read more about margins of victory in the 2012 U.S. Senate elections.

U.S. House

HIGHLIGHTS

The average margin of victory of all congressional districts was 31.85%.

The average margin of victory for Democratic winners was 35.7%, while the average for Republicans was 28.6%.

The smallest margin of victory was North Carolina's 7th Congressional District, where incumbent Mike McIntyre (D) defeated David Rouzer (R) by 0.2 percent (654 votes).

The largest margin of victory where both major parties fielded a general election candidate was in New York's 15th Congressional District, where incumbent Jose Serrano defeated Frank Della Valle (R) by 83%.

Click here to read more about margins of victory in the 2012 U.S. House elections.

See also

• Congressional Analysis Archive
• Margin of victory
• Ballotpedia's Election Analysis Hub, 2024

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