Incumbent Democratic President Franklin D. Roosevelt defeated Republican businessman Wendell Willkie to be reelected for an unprecedented third term in office.

The election was contested in the shadow of World War II in Europe, as the United States was finally emerging from the Great Depression.

[3] He and his allies sought to defuse challenges from other party leaders such as James Farley and Vice President John Nance Garner.

The 1940 Democratic National Convention re-nominated Roosevelt on the first ballot, while Garner was replaced on the ticket by Secretary of Agriculture Henry A. Wallace.

Willkie, a dark horse candidate, unexpectedly defeated conservative Senator Robert A. Taft and Manhattan District Attorney Thomas E. Dewey on the sixth presidential ballot of the 1940 Republican National Convention.

[4] Willkie, who had not previously run for public office, conducted an energetic campaign, managing to revive Republican strength in areas of the Midwest and Northeast.

He criticized perceived incompetence and waste in the New Deal, warned of the dangers of breaking the two-term tradition, and accused Roosevelt of secretly planning to take the country into World War II.

Garner was a Texas conservative who had come to disagree with Roosevelt's liberal economic and social policies, and declined to run for a third term as vice president.

First Lady Eleanor Roosevelt came to Chicago to vouch for Wallace, and he won the vice-presidential nomination with 626 votes to 329 for House Speaker William B. Bankhead of Alabama.

Dewey, the District Attorney for Manhattan, had risen to national fame as the "Gangbuster" prosecutor who had sent numerous infamous Mafia figures to prison, most notably Lucky Luciano, the organized-crime boss of New York City.

Taft's outspoken isolationism and opposition to any American involvement in the European war convinced many Republican leaders that he could not win a general election, particularly as France fell to the Nazis in June 1940 and Germany threatened the United Kingdom.

In 1940, Vandenberg was also an isolationist (he would change his foreign-policy stance during World War II) and his lackadaisical, lethargic campaign never caught the voters' attention.

Willkie, a native of Indiana and a former Democrat who had supported Franklin Roosevelt in the 1932 United States presidential election, was considered an improbable choice.

Furthermore, unlike the leading Republican candidates, Willkie was a forceful and outspoken advocate of aid to the Allies of World War II, especially the United Kingdom.

The German Army's rapid Blitzkrieg campaign into France in May 1940 shook American public opinion, even as Taft was telling a Kansas audience that America needed to concentrate on domestic issues to prevent Roosevelt from using the war crisis to extend socialism at home.

As the delegates were arriving in Philadelphia, Gallup reported that Willkie had surged to 29%, Dewey had slipped five more points to 47%, and Taft, Vandenberg and Hoover trailed at 8%, 8%, and 6% respectively.

At the 1940 Republican National Convention itself, keynote speaker Harold Stassen, the Governor of Minnesota, announced his support for Willkie and became his official floor manager.

Gallup found the same thing in polling data not reported until after the convention: Willkie had moved ahead among Republican voters by 44% to only 29% for the collapsing Dewey.

The key moments came when the delegations of large states such as Michigan, Pennsylvania, and New York left Dewey and Vandenberg and switched to Willkie, giving him the victory on the sixth ballot.

[13] However, the American Institute of Public Opinion, responsible for the Gallup Poll, avoided predicting the outcome, citing a four percent margin of error.

Willkie was a fearless campaigner; he often visited industrial areas where Republicans were still blamed for causing the Great Depression and where Roosevelt was highly popular.

Roosevelt was the third of just four presidents in United States history to win re-election with a lower percentage of the electoral vote than in their prior elections, the other three were James Madison in 1812, Woodrow Wilson in 1916 and Barack Obama in 2012.

Additionally, Roosevelt was the fourth of only five presidents to win re-election with a smaller percentage of the popular vote than in prior elections, the other four are James Madison in 1812, Andrew Jackson in 1832, Grover Cleveland in 1892, and Obama in 2012.

Although at a rate lower than 1936, Roosevelt maintained his strong majorities from labor unions, big city political machines, ethnic minority voters, and the traditionally Democratic Solid South.

As of 2024, Roosevelt was the sixth of eight presidential nominees to win a significant number of electoral votes in at least three elections, the others being Thomas Jefferson, Henry Clay, Andrew Jackson, Grover Cleveland, William Jennings Bryan, Richard Nixon, and Donald Trump.

Later, he directed some of these funds towards supporting anti-Roosevelt radio broadcasts by the isolationist labor leader John L. Lewis, with the aim of impeding Roosevelt's re-election bid.