According to the current conventional wisdom, the South gave up the attempt to abolish slavery after reformers' first real test. The Missouri Controversy of 1819-20 supposedly annihilated "Jeffersonian antislavery," with Thomas Jefferson himself slaying his offspring. Jefferson's 1820 letter after the Missouri Compromise to Congressman John Holmes is the supposed critical proof that the Sage of Monticello drew close to John C. Calhoun.I plan to discuss his analysis further in following posts.
Jefferson's Holmes letter does reveal revised tactics. But this and other evidence hardly shows that southern apologists became warriors for slavery's perpetuation. Instead, the Missouri Controversy scared the Jeffersons towards new efforts to remove slaves from America.
But Freehling makes several points critical to understanding how the slavery issue played out in real time. The Missouri crisis was an inflection point in various ways. After that time, the typical justifications of slavery changed from the necessary evil kind of justification favored by Jefferson to the Calhounian defense of slavery as a good thing and the necessary foundation for white republican civilization. It also marked a turning point in which Northern Republicans and the remnants of the Federalist Party embraced emancipation as a partisan club to use against the southern Republicans and the Jacksonian Democrats north and south. And it marked a public outbreak of the real contradictions between democracy and slavery, and between democracy and the economic liberalism of the time. American slavery was a capitalist institution. And the defense of private property in the US of 1820 also meant the defense of private property in human flesh, which is what slavery was.