Average margin of victory in last year’s U.S. House races was lowest since at least 2012
The average margin of victory (MOV) in last year’s U.S. House elections was 28.8 percentage points, down from 31.8 percentage points in 2018 and the narrowest average MOV in U.S. House elections since at least 2012. Ballotpedia has analyzed the margin of victory in congressional elections after each election cycle from 2012 to the present.
The average Democratic winner of a U.S. House election had a MOV of 31.5 percentage points. The average Republican winner’s MOV was 26.0 percentage points.
The margin of victory refers to the difference between the vote shares of the winning and losing candidates. For example, if Candidate A defeated Candidate B, 55% to 45%, the margin of victory is 10 percentage points.
The average MOV in last year’s 35 Senate elections was 18.1 percentage points. That’s up from 2018’s 16.8 percentage point MOV, but less than any other year since 2012.
In 2020, there were:
- Five Senate races decided by margins less than five percentage points—Democrats won four of these and Republicans won one,
- Twelve Senate races decided by margins between five and 15 percentage points—Republicans won eight and Democrats won four, and
- Eighteen Senate races decided by margins more than 15 percentage points—Republicans won 11 and Democrats won seven.
In 2018, the closest U.S. House election was incumbent Rob Woodall’s (R) 433-vote win over Carolyn Bourdeaux (D) in Georgia’s 7th Congressional District. Last year, three U.S. House elections were decided by margins of 500 votes or fewer.
- Iowa’s 2nd Congressional District—Mariannette Miller-Meeks’ (R) defeated Rita Hart (D) by six votes in the closest U.S. House election since 1984.
- New York’s 22nd Congressional District—Claudia Tenney (R) currently leads incumbent Anthony Brindisi (D) by 29 votes. These results have not yet been certified, and the outcome of this election has not yet been determined.
- California’s 25th Congressional District—Incumbent Mike Garcia (R) defeated Christy Smith (D) by 333 votes.
Republican candidates won seven of the closest U.S. House races. Democrats won two of those races, and the outcome of New York’s 22nd District has not been decided.
Of the 434 called U.S. House elections, there were:
- Thirty-six decided by margins less than five percentage points. Democratic candidates won 19, and Republicans won 17,
- Eighty-two decided by margins between five and 15 percentage points, with Republicans winning 44 and Democrats winning 38.
- Three hundred and sixteen decided by more than 15 percentage points. Democrats won 165 of these, and Republicans won 151.
The map below shows the location of all U.S. House races decided by a MOV of 5 percentage points or less. Democrats won in the 19 districts shaded in blue, and Republicans won in the 17 districts colored red.
Biden to be inaugurated as 46th president
Later today, President-elect Joe Biden (D) will be inaugurated as the nation’s 46th president. Kamala Harris (D-Calif.) will also be sworn in as the 49th vice president of the United States, becoming the first Black woman and person of South Asian descent to serve in the office. The events are scheduled to begin at 11:30 a.m. ET.
Due to security concerns stemming from the breach of the U.S. Capitol, up to 25,000 National Guard members are expected to be in Washington, D.C. The National Mall is closed to the general public, and there will be no public parade from the Capitol to the White House.
The ceremony will be broadcast on major television networks and streamed online on various platforms. President Donald Trump (R) will not participate in the event. The last president to skip his successor’s inauguration for political reasons was Andrew Johnson in 1869.
After Harris is inaugurated as vice president, she is expected to swear in Jon Ossoff (D-Ga.), Raphael Warnock (D-Ga.), and Alex Padilla (D-Calif.) to the U.S. Senate.
Register for our Jan. 21 briefing on Pivot County election results
We’re hosting our first webinar of the year on Thursday—Jan. 21—with an in-depth look at Pivot Counties. Ballotpedia identified 206 counties nationwide that voted for Barack Obama (D) in the 2008 and 2012 presidential elections and Donald Trump (R) in 2016.
We’ll start with why we began tracking these counties in 2016, and we’ll introduce you to our two new definitions—Retained and Boomerang Counties. Retained Pivot Counties are those Trump won in 2020, while Joe Biden won Boomerang Pivot Counties.
In this week’s briefing, we’ll review the results from these counties and the numbers of counties in each category. We’ll also explore Pivot County demographics and turnout, what role these counties played in 2020, and how they might continue to shape politics in the future.
The briefing is at 11 a.m. CT on Jan. 21, and you can register—for free—by clicking on the link below. And if you can’t listen to the presentation live, we’ll send you a link to the recording when it’s available so you can watch it on your schedule. I hope you’ll join us!