Two years earlier, in 1848, the Whig Party selected Zachary Taylor, a successful American general during the Mexican–American War, as the party's presidential nominee. For Taylor's running mate, the party selected Millard Fillmore, a loyal supporter of defeated presidential candidate Henry Clay. The Whigs won the election, but the Democrats maintained control of both the House of Representatives and the Senate. Taylor's presidency was consumed with addressing the status of slavery in the region ceded by Mexico following the Mexican–American War. After taking office, Vice President Fillmore's views were not considered because of the efforts of editor Thurlow Weed, who viewed Fillmore as a rival to Weed's close political ally, William H. Seward. It looked as if Fillmore would be relegated to a role of political irrelevance and obscurity.
That changed on the evening of July 9, 1850, when Fillmore received news that Taylor had died and he was now President. After being notified of Taylor's death, Fillmore went to the House of Representatives Chamber in the U.S. Capitol the following day, where he took the presidential oath of office, administered by William Cranch, chief judge of the U.S. Circuit Court.
Before and during Taylor's presidency, a key issue was the status of slavery in the territories acquired in the Mexican War. It was a fiercely divisive issue. 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 took this to mean that slavery was legal in all of the land acquired from Mexico south of that line. During the Mexican–American War, a Northern member of Congress had put forth the Wilmot Proviso, a legislative proposal that would have banned slavery in all territories acquired in the Mexican–American War. This was never adopted by Congress, but the debate over the Wilmot Proviso had had heightened tensions regarding slavery.
The territories of California and New Mexico, as well the state of Texas, had been annexed in 1845. Because California lacked an organized territorial government, and after the start of the gold rush, hundreds of slaves were imported into California to work the gold mines, provoking a harsh reaction from competing miners. With the approval of military governor Bennet C. Riley, in 1849 Californians held a constitutional convention and wrote a new constitution that would ban slavery in California.
Texas claimed all of the land acquired from Mexico east of the Rio Grande, including parts of the former Mexican state of New Mexico. The inhabitants of New Mexico had resisted Texan control and had prohibited slavery for a long time. Many New Mexicans opposed joining Texas because Texas and New Mexico had a history of conflict. Outside of Texas, many Southern leaders supported Texas's claims to New Mexico in order to secure as much territory as possible for the expansion of slavery. President Taylor was opposed to Texas's claim to New Mexico, and he favored quickly granting statehood to both California and New Mexico.
On January 29, 1850, Senator Henry Clay introduced a plan which looked for a compromise that would appease the competing factions over the issue of slavery. His legislative package called for the admission of California as a free state, the cession by Texas of some of its northern and western territorial claims in return for debt relief, the establishment of New Mexico and Utah territories, a ban on the importation of slaves into the District of Columbia for sale, and a stronger fugitive slave law. South Carolina Senator John C. tried to rally Southerners against the compromise, and anti-slavery Northerners like William Seward and Salmon Chase also opposed the compromise. Clay's proposal did attract a large measure of support from both Southern and Northern leaders.
Clay had originally wanted a vote on each of his proposals separately, but Senator Henry S. Foote of Mississippi convinced him to combine the proposals regarding California's admission and the disposition of Texas's borders into one bill. The strategy failed and the bill lacked the necessary votes to pass. Debate over the bill continued. Other compromises were considered. Foote suggested that California be split into two states, with the division at the 35th parallel north, but President Taylor opposed this. He favored granting California statehood immediately. Texas Governor Peter Hansborough Bell protested the organization of New Mexico's constitutional convention, which went ahead with the approval of Taylor and the military government of New Mexico under General Stephen W. Kearny, set up during the Mexican–American War. Taylor urged that Congress immediately grant statehood to both California and New Mexico. Taylor died in July 1850, with none of the major domestic issues facing his presidency being settled.
The debate over slavery in the territories continued after Taylor's death. Fillmore Clay's compromise, but did not believe that it could pass in a single bill. With the apparent collapse of the bill, Clay took a temporary leave from the Senate, and Democratic Senator Stephen A. Douglas of Illinois took over the lead in advocating for a compromise based on Clay's proposals. Rather than passing the proposals as one bill, Douglas would seek to pass each proposal one-by-one.
Fillmore reinforced federal troops in the disputed New Mexico region, and warned Texas Governor Bell that the US Army would intervene if Bell caused any trouble. In an August 6, 1850 message to Congress, Fillmore denied Texas's claims to New Mexico, asserting that United States had promised to protect the territorial integrity of New Mexico in the Treaty of Guadalupe Hidalgo. Fillmore also urged Congress to settle the boundary dispute as quickly as possible, and indicated support for providing monetary compensation to Texas in return for the establishment of New Mexico Territory. Texas's U.S. Senators, Sam Houston and Thomas Jefferson Rusk agreed to support Douglas's compromise. With their support, a senate bill providing for a final settlement of Texas's borders won passage days after Fillmore delivered his message. Under the terms of the bill, the U.S. would assume Texas's debts, while Texas's northern border was set at the 36° 30' parallel north (the Missouri Compromise line). The bill had the support of a bipartisan coalition of Whigs and Democrats from both sections, with most opposition to the bill coming from the South. 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.
The debate then moved to the House of Representatives, where the Senate's proposed settlement of the Texas-New Mexico boundary faced intense opposition from many Southerners, as well as from some Northerners who opposed giving Texas monetary compensation. After a series of close votes, the House voted to approve a Texas bill similar to that which had been passed by the Senate. Following that vote, the House and the Senate agreed on each of the major issues, including the banning of the slave trade in Washington. Fillmore quickly signed each bill into law, except for the Fugitive Slave Act of 1850. He signed that bill into law only after Attorney General Crittenden gave him an opinion that the law was constitutional.
At the time, it looked as if the passage of the Compromise of 1850 had saved the union. Fillmore himself described the Compromise of 1850 as a "final settlement" of sectional issues. But it was clear that many southerners, as well as many northerners, were unhappy with the result. Southern leaders like Robert Rhett and William Lowndes Yancey urged secession from the United States. Fillmore took the threat of secession seriously, and on the advice of General Winfield Scott he strengthened the garrisons of federal forts in Charleston and other parts of the South.
At that time, elections were held for the House of Representatives annually, and in 1850 and 1851 the Whigs lost 24 seats in the House. Only 7 of those went to the Democratic Party, with the Unionist Party (a pro-compromise third party mostly from the border states) winning 15 seats, and the Southern Rights Party winning 8. The Free-Soil Party lost all 4 seats it held in Congress. Unionists won victories in Georgia, Alabama, and Mississippi. Even in South Carolina, the state most open to talk of secession, voters rejected the possibility of unilateral secession from the United States. The victory of pro-compromise Southern politicians in several elections, along with Fillmore's attempts at diligently enforcing the Fugitive Slave Clause, temporarily quieted Southern calls for secession.
In the aftermath of the Compromise politicians such as William H. Seward and Salmon P. Chase began contemplating the creation of a new major party explicitly opposed to the extension of slavery. Fillmore would be the last Whig President. The compromise proved only to be a band-aid solution to a serious wound that the nation had suffered. The clash between those favoring abolition and those calling for secession would ultimately lead to civil war.