By confronting Stephen Douglas with the words of a moderate politician disinterested in slavery who avowed the sacred permanence of the Missouri Compromise, both reinforced his own argument for the same position and forced the Little Giant to face his own speech. One need not be an antislavery ideologue, like Salmon P. Chase, William Seward, or Lincoln himself might come across. In Douglas’ mind, and the minds of his supporters, those men might all share the same flesh. But Douglas himself? Surely not! The Little Giant might fancy himself a great statesman, with some reason, and see a president in the mirror every morning, but never an antislavery fanatic.
But Lincoln did dig up a quote from 1849. Douglas always said that things changed in 1850. Before that, he accepted the Missouri Compromise as the best the nation could do. As Douglas now told it, he always preferred popular sovereignty. The Little Giant further insisted that the antislavery sorts fouled up the whole business, necessitating the change in policy.
A bill was duly got up, for the purpose, and was progressing swimmingly, in the House of Representatives, when a member by the name of David Wilmot, a democrat from Pennsylvania, moved as an amendment “Provided that in any territory thus acquired, there shall never be slavery.”
This is the origin of the far-famed “Wilmot Proviso.” It created a great flutter; but stuck like wax, was voted into the bill, and the bill passed with it through the House. The Senate, however, adjourned without final action on it and so both the appropriation and proviso were lost, for a time.
But the war went on. Polk asked again. Congress went to work again. The proviso came up again. The bill died again. A new Congress came in December, 1847, and Lincoln himself
was in the lower House that term. The “Wilmot Proviso” or the principle of it, was constantly coming up in some shape or other, and I think I may venture to say I voted for it at least forty times; during the short term I was there. The Senate, however, held it in check, and it never became law.
In due course Nicholas Trist negotiated a proviso-free treaty handing over to the United States the vast Southwest. The Mexican Cession ran right west of the Louisiana Purchase. Why not draw the Missouri Compromise line out to the Pacific? Douglas thought that a great idea at the time:
On Judge Douglas’ motion a bill, or provision of a bill, passed the Senate to so extend the Missouri line. The Proviso men in the House, including myself, voted it down, because by implication, it gave up the Southern part to slavery, while we were bent on having it all free.
That point really does cut both ways. The South would not tolerate a Mexican Cession all free. Antislavery men would not tolerate a Mexican Cession all slave. This left the issue in doubt as the 1840s wound down. Did principle or precedent require either side to accept extending the Missouri line? Perhaps, both other principles came into play as well. If one saw slavery as right, why should it suffer any special restrictions? If one saw it as wrong, why should any new territory be reserved for it at the expense of freedom?
On paper, the sacred pact applied only to the Louisiana Purchase. The provision, which Douglas favored at the time, that extended the line across Texas contained within it the tacit admission that the line did not extend on its own across Texas. Each new parcel of land, at least in principle, opened the question anew. If both antislavery and proslavery men departed from established precedent, they did so in accord with a separate precedent that each territory needed its own slavery settlement.