The 1840 Democratic National Convention was held in Baltimore, Maryland, from May 5 to May 6. The Democratic Party re-nominated President Martin Van Buren by acclamation, but failed to select a nominee for vice president. Van Buren is the only major party presidential nominee since the ratification of the 12th Amendment to seek election without a running mate. Dragged down by the unpopularity of the Panic of 1837, Van Buren was defeated by the Whig Party's ticket in the 1840 presidential election.

The 1840 United States presidential election was the 14th quadrennial presidential election, held from Friday, October 30 to Wednesday, December 2, 1840. Economic recovery from the Panic of 1837 was incomplete, and Whig nominee William Henry Harrison defeated incumbent President Martin Van Buren of the Democratic Party. The election marked the first of two Whig victories in presidential elections, but was the only one where they won a majority of the popular vote. This was the third rematch in American history, which would not occur again until 1892.