The Compromise of 1850 temporarily settled the status of slavery in the lands acquired as result of the Mexican–American War, and led to a brief truce in the escalating political battle between slave and free states.

For Taylor's running mate, John A. Collier convinced his fellow Whigs to nominate Fillmore, a loyal supporter of defeated presidential candidate Henry Clay.

[2] Despite the Whig presidential victory, Democrats maintained control of both the House of Representatives and the Senate, preventing the reversal of outgoing President James K. Polk's policies on the tariff and other issues.

After the death of Associate Justice John McKinley in mid-1852, Fillmore successively nominated Edward A. Bradford, George Edmund Badger, and William C. Micou.

[21] In 1820, Congress had agreed to the Missouri Compromise, which had banned slavery in all lands of the Louisiana Purchase north of the 36° 30' parallel, and many Southerners sought to extend this line to the Pacific Ocean.

[33] In the final months of his life, Senator Calhoun attempted to rally Southerners against the compromise, arguing that it was biased against the South because it would lead to the creation of new free states.

[38] Clay hoped that this combination of measures would convince congressmen from both North and South to support the overall package of laws even if they objected to specific provisions.

[39] Clay's proposal attracted the support of some Northern Democrats and Southern Whigs, but it lacked the backing necessary to win passage, and debate over the bill continued.

With Fillmore's support, Senator James Pearce of Maryland helped defeat Clay's compromise bill by proposing to remove a provision related to the Texas-New Mexico boundary.

[48] The Senate quickly moved onto the other major issues, passing bills that provided for the admission of California, the organization of New Mexico Territory, and the establishment of a new fugitive slave law.

[50] The Senate's proposed settlement of the Texas-New Mexico boundary faced intense opposition from many Southerners, as well as from some Northerners who believed that the Texas did not deserve monetary compensation.

[59] Fillmore hoped that slavery would one day cease to exist in the United States, but he believed that it was his duty to zealously enforce the Fugitive Slave Act.

[62] Harriet Beecher Stowe wrote the novel Uncle Tom's Cabin in response to the Fugitive Slave Act, and its publication in 1852 further raised sectional tensions.

There was less support for outright secession in the North than in the South, but in the aftermath of the Compromise politicians such as Seward began contemplating the creation of a new major party explicitly opposed to the extension of slavery.

[64] Despite the disruptions caused by the debate over the Compromise, no major long-term partisan realignment occurred during Fillmore's presidency, and both parties remained intact for the 1852 presidential election.

[68] To deescalate the Mormon issue, Fillmore appointed Church of Jesus Christ of Latter-day Saints leader Brigham Young as the first governor of Utah Territory in September 1850.

[70] In August 1850, the social reformer Dorothea Dix wrote to Fillmore, urging support for her proposal in Congress for land grants to finance asylums for the impoverished mentally ill.

[71] On September 21, 1850, Fillmore signed the Donation Land Claim Act of 1850 which was intended to promote homestead settlements in the Oregon Territory, but ended up displeasing Native Americans.

[77] France under Napoleon III sought to annex Hawaii, but backed down after Fillmore issued a strongly worded message warning that "the United States would not stand for any such action.

Fillmore, Webster and the Spanish government worked out a series of face-saving measures, including the release of the American prisoners, that settled a brewing crisis between the two countries.

Fillmore's enforcement of the Fugitive Slave Act had made him unpopular among many in the North, but he retained considerable support from the South, where he was seen as the only candidate capable of uniting the party.

[82] Webster hoped that his pro-Compromise stance would help him garner support throughout the country, but his reputation as the spokesman for New England limited his appeal outside of his home region, especially in the South.

[84] A third candidate emerged in the form of General Winfield Scott, who, like previously successful Whig presidential nominees William Henry Harrison and Zachary Taylor, had earned fame for his martial accomplishments.

But by the time of the May 1852 Democratic National Convention, former Secretary of State James Buchanan of Pennsylvania had eclipsed Douglas, who had made several enemies in the party and faced rumors about his drinking.

Two days later, at the urging of Southern delegates, the Whig National Convention passed a party platform endorsing the Compromise as a final settlement of the slavery question.

[97] Finkelman argues that the central accomplishment of Fillmore's tenure, the Compromise of 1850, should instead be called the "Appeasement of 1850" due to its abandoning of the Wilmot Proviso, thereby opening up all of the territories of the Mexican Cession to slavery.

[98] On a more favorable note, historian Elbert B. Smith found him to be "a conscientious president" who chose to honor his oath of office and enforce the Fugitive Slave Act, rather than govern based on his personal preferences.

[99] According to Smith, the enforcement of the Fugitive Slave Act has given Fillmore an undeserved pro-southern reputation, and the evaluation of his presidency has also suffered because "even those who give him high marks for his support of the compromise have done so almost grudgingly, probably because of his Know-Nothing candidacy in 1856".

[100] Paul G. Calabresi and Christopher S. Yoo, in their study of presidential power, deemed Fillmore "a faithful executor of the laws of the United States—for good and for ill".

[102] Benson Lee Grayson suggested that Fillmore's constant attention to Mexico avoided a resumption of the war and laid the groundwork for the Gadsden Treaty during Pierce's presidency.