Fillmore was a New Yorker and represented the state in Congress from 1837 to 1843. He lost election for Governor of New York in 1844, but was selected to be Zachary Taylor's running mate in the 1848 election. The nomination of Taylor for president angered supporters of Henry Clay as well as those opposed to allowing slavery in the territories gained in the Mexican–American War. The Whigs nominated Fillmore for vice president because Fillmore came from a non-slave state and delegates believed he would help the ticket carry his populous home state of New York.
Taylor and Fillmore disagreed on the question of slavery, but not in the manner that people might imagine. Taylor wanted the new states to be free states, while Fillmore supported slavery in those states to appease the South. Fillmore said "God knows that I detest slavery, but it is an existing evil ... and we must endure it and give it such protection as is guaranteed by the Constitution." Apparently he was personally opposed to slavery on principle, but put his principles behind his politics. The debate over the issue was wild and wooly and as Vice-President, Fillmore was responsible for presiding over the senate. During one debate, Senator Henry S. Foote of Mississippi pulled a pistol on Senator Thomas Hart Benton of Missouri.
When Taylor died suddenly on July 9, 1850, Fillmore became president and the landscape changed on the slavery issue. Fillmore had very different views on the slavery than Taylor. Before Taylor's death, Fillmore said that, as President of the Senate, he would give his tie-breaking vote to the Missouri Compromise. When Fillmore took office, Taylor's entire cabinet offered their resignations and Fillmore accepted them all and appointed men who also favored the Compromise. When the compromise finally came before both Houses of Congress, it was a very watered down bill. This angered Fillmore and he urged Congress to pass the original bill. This move provoked more conflict in which forces for and against slavery fought over every word of the bill. The fight exhausted poor old Henry Clay and he left Washington to recuperate, passing leadership to Senator Stephen A. Douglas of Illinois.
On August 6, 1850, Fillmore took steps to helped shift a number of northern Whigs in Congress away from their insistence upon the Wilmot Proviso (the stipulation that all land gained by the Mexican War must be closed to slavery.) Douglas's strategy in Congress combined with Fillmore's actions helped the Compromise gain strength. Douglas presented five separate bills to the Senate which would:
1. Admit California as a free state.
2, Settle the Texas boundary and compensate the state for lost lands.
3. Grant territorial status to New Mexico.
4. Require federal officers to assist slaveholders seeking escaped slaves (the Fugitive Slave Act)
5. Abolish the slave trade, but not slavery, in the District of Columbia.
Each measure passed and, by September 20, President Fillmore had signed them into law. But in the process he split the Whig Party. Fillmore's greatest difficulty with the fugitive slave law. He tried to appease both northern and southern Whigs. He called for enforcing the fugitive slave law in the North, and by preventing the annexation of Cuba (which southernors wanted as another slave state.) In the end, everyone was mad at him.
Fillmore was not renominated when his term came to an end. Northern Whigs refused to forgive him for having signed the Fugitive Slave Act. He ran again for President in 1856 as the candidate for the Know-Nothing Party (their slogan was "I know nothing but my country, my whole country and nothing but my country) and his running mate was Andrew Jackson Donelson, nephew of former president Andrew Jackson. Fillmore and Donelson finished third, carrying only the state of Maryland and its eight electoral votes; but he won 21.6% of the popular vote, one of the best showings ever by a Presidential third-party candidate.
In retirement, Fillmore continued to feel that apperasement of southern slave interests was necessary. He blamed the Republican Party for the subsequent disunion, althout he was also an outspoken critic of secession and was also critical of President James Buchanan for not immediately taking military action when South Carolina seceded. Throughout the Civil War, Fillmore opposed President Abraham Lincoln and during Reconstruction he supported President Andrew Johnson. He died in 1874 from a stroke.