U.S. Presidential Voting History by State
After a tumultuous election, all states have now certified their 2020 presidential voting results. Which states changed party allegiance, and how do the results compare to previous years?
In this graphic, we use data from the U.S. National Archives and the MIT Election Data and Science Lab to show U.S. presidential voting history by state since 1976.
Note: this post has been updated on January 19, 2021 to reflect the latest data.
Each State’s Winning Party
To calculate the winning ratio, we divided the votes for the state’s winning party by the total number of state votes. Here’s another look at the same data, visualized in a different way.
This graphic was inspired by this Reddit post.
As the voting history shows, some states—such as Alaska, Oklahoma, and Wyoming—have consistently supported the Republican Party. On the other hand, Hawaii, Minnesota, and the District of Columbia have been Democrat strongholds for many decades.
The District of Columbia (D.C.) is a federal district, and is not part of any U.S. State. Its population is urban and has a large percentage of Black and college-educated citizens, all of which are groups that tend to identify as Democrat.
Swing states typically see a close contest between Democrats and Republicans. For example, Florida’s average margin of victory for presidential candidates has been just 2.7% since 1996. It’s often seen as a key battleground, and for good reason: the state has 29 electoral college votes, meaning it has a high weighting in the final outcome.
Memorable Election Years
Within U.S. presidential voting history, some election results stand out more than others. In 1984, President Reagan was re-elected in a landslide victory, winning 49 out of 50 states. The remarkable win has been credited to the economic recovery during Reagan’s first term, Reagan’s charisma, and voters’ opposition to the Democrat’s planned tax increases.
In 1992, self-made Texas billionaire Ross Perot ran as a third-party candidate. He captured almost 19% of the popular vote, the highest percentage of any third-party presidential candidate in over 80 years. While he gained support from those looking for a change from traditional party politics, Bill Clinton ultimately went on to win the election.
Most recently, the 2020 election had a record voter turnout, with 66.3% of the eligible population casting a ballot. There was also a record number of mail-in ballots due to the COVID-19 pandemic. This led to widespread allegations of voter fraud, with President Trump and his allies filing 62 lawsuits seeking to overturn election results. In the end, 61 of the lawsuits were defeated and congress confirmed Joe Biden’s victory.
Voting History of Swing States
Both Trump and Biden focused on battleground states in 2020, but where were they successful? Here are nine of the swing states, and their voting history over the last two elections.
| 2020 Winning Ratio | 2020 Margin of Victory | 2016 Winning Ratio | 2016 Margin of Victory | |
|---|---|---|---|---|
| Arizona | 49.4% Democrat | 0.31% | 48.7% Republican | 3.60% |
| Florida | 51.2% Republican | 3.36% | 49.0% Republican | 1.20% |
| Georgia | 49.5% Democrat | 0.24% | 50.8% Republican | 5.20% |
| Iowa | 53.2% Republican | 8.20% | 51.2% Republican | 9.40% |
| Michigan | 50.6% Democrat | 2.78% | 47.5% Republican | 0.20% |
| North Carolina | 50.1% Republican | 1.35% | 49.8% Republican | 3.60% |
| Ohio | 53.3% Republican | 8.03% | 51.7% Republican | 8.10% |
| Pennsylvania | 50.0% Democrat | 1.16% | 48.9% Republican | 0.70% |
| Wisconsin | 49.5% Democrat | 0.63% | 47.2% Republican | 0.70% |
The Republican party won four of the swing states in 2020, including Florida. However, 2020 was the first year since 1964 that the candidate who won Florida did not go on to win the election.
Five of the states—Arizona, Georgia, Michigan, Pennsylvania, and Wisconsin—flipped allegiance to the Democrats. In Georgia, the margin of victory was as small as 0.24% or about 12,000 votes. Ultimately, winning over these states helped lead to a Biden victory.
