Millard Fillmore was the second man to enter the White House by the side door. John Tyler had been the first, and though he effectively settled the question of whether an unelected president was really the president—in the affirmative—he left open the question of whether an unelected president really mattered. Tyler's inherited presidency passed uneventfully, except for squabbling among members of his own Whig party, who denied him nomination for a full term of his own.
Fillmore, by contrast, faced an extremely eventful decision at the moment Zachary Taylor died and Fillmore took his place. The question of slavery in a republic had grown from being an afterthought at the Constitutional Convention of 1787 to an issue that pervaded every aspect of American political life. The discovery of gold in California in 1848 had led to a rush of population there, soon filling California with enough people to qualify for statehood. Californians drafted a constitution and sent it to Congress for approval. Northerners were pleased with the constitution, which forbade slavery; Southerners were displeased on account of the ban.
Decades earlier the South had lost any chance for control of the House of Representatives, having a smaller population than the North and one that was growing more slowly. Yet it retained parity in the Senate, where the 15 free states of the North were balanced by the 15 slave states of the South. Admission of free California would tip the balance to the North. Some southerners wanted simply to refuse to admit California at all. Wiser heads recognized that this was not a sustainable policy. So they demanded a quid pro quo.
Henry Clay, the venerable statesman from Kentucky, came out of retirement to fashion a final compromise in his career of discovering common ground between the sections. The decisive elements of Clay’s compromise were two: admission of California as a free state, and a newly stringent fugitive slave act. Southern slave owners had long complained of northern complicity in the escape of southern slaves. This complicity violated the Constitution, which clearly specified an obligation of the states to assist in the return of escaped slaves, although it avoided the term “slave,” in favor of “person held to service or labor." The southerners insisted that this obligation be enforced.
What came to be called the Compromise of 1850 had a principal characteristic of many good compromises: it produced outrage on both sides. Many southerners predicted that the loss of parity in the Senate would leave the South at the mercy of antislavery northerners. Many northerners bridled at being forced into complicity in the return of men and women whose only crime was to seek their freedom.
Millard Fillmore had to decide whether to sign the compromise or veto it. As vice president he had fulfilled his constitutional duty of presiding over the Senate, including during the debate over the compromise. He took no part in the debate and gave no public hint as to his opinions. In private, though, he indicated that if called upon to cast the tiebreaking vote—as vice presidents are permitted to do in case of Senate deadlock—it would be in favor of the compromise.
The package didn't require Fillmore's vote in the Senate. It passed on its own. But it did require his approval as president following the sudden death of Zachary Taylor. Or at least it required his non-veto. A president does not have to sign an approved bill for it to become a law; it does so on its own in the absence of a veto.
Fillmore had been nominated for the vice presidency not because he was like Taylor but because he was unlike Taylor. The Whig party was splitting into northern and southern factions. Taylor was a Virginian and a favorite of the southerners. New Yorker Fillmore was added to the ticket to please the northerners. The death of Taylor shifted the presidency, in effect, from the South to the North.
Vetoes were still rare in the mid-19th century. Presidents had expressly negated fewer than two dozen approved bills by then. (Another fifteen been pocket-vetoed: allowed to die without signature at the end of a legislative session.) Fillmore understood that he lacked a mandate, not having been elected president. He would be perceived as having less standing to cast a veto.
Personally favoring the compromise, and disinclined as an unelected president to exercise the veto power, Fillmore nonetheless had to consider what approving the compromise might mean. It would aggravate tensions within his own Whig party and quite possibly end his political career. Upstate New York, the region of his birth, was a hotbed of abolitionism, and the abolitionists were hurling anthemas at compromises with slavery and the compromisers who made them.
Fillmore had to consider the effect of the compromise on the Union. Henry Clay had designed the compromise to hold the Union together. Stephen Douglas of Illinois, who helped guide the package through Congress, was a stout Unionist too. But perhaps their efforts were misguided. The forces already unleashed by the debate over the compromise suggested that far from securing the Union, it might blow the Union apart.
Fillmore took his own fate, the fate of his party and the fate of the Union into his hands and signed the compromise.
He survived the rest of the term he had inherited from Taylor. But his party wanted nothing more to do with him. This was no big loss, for the Whigs themselves shortly disintegrated, riven by the sectional dispute.
As for the Union, the compromise perhaps delayed the moment of truth. But by 1860, the sectional forces had grown so divisive as to make secession almost inevitable and civil war likely.