Leibiger's argument about correcting traditional interpretations of Jefferson's distress over events around the Missouri Compromise doesn't strike me as particularly notable, although it strikes me as obviously correct. He argues that he calculated his statements to political effect, which seems pretty obvious to me. He writes, "Dumas Malone's statement that 'there is no reason to believe that he ... tried to have any direct influence on the course of events in the crisis' seems too naive."
But that statement by Dumas, which is from the chapter on the Missouri Compromise in The Sage of Monticello (1981) from which I quoted in the last post in this series. It stuck out to me, because it seems inconsistent with the story Dumas is telling there. So whether Leibiger's argument about the nuances of conventional interpretations is something I'll gladly leave to the professional Jefferson scholars.
But I find Leibiger's concluding judgment to be a very useful perspetive:
Historians long have taken Jefferson's shrill rhetoric on the Missouri Crisis at face value, probably because it was so prophetic; but prophecy was never his intention. Jefferson and others used threats and bullying to coerce a compromise and preserve the Union. The strategy worked in the short term, but in the long run it led to southern proslavery intransigence and finally civil war. From Jefferson's perspective, issuing frightful warnings may have seemed like a sound approach to sectional bickering. During the revolutionary years, southern ultimatums had produced compromises for the Union, most notably at the 1787 Federal Convention. But in the 1820s and 1830s, many Americans began placing other priorities-including the morality of owning slaves - above constitutional unionism. Still unaware of these shifting sentiments, Jefferson employed familiar tactics that had worked in the eighteenth century. The gradual emergence of both "fire-eaters" in the South and abolitionists in the North guaranteed that his approach would backfire as passion and single-issue fanaticism replaced moderation and forbearance. Jefferson's close friend James Madison, who seemed to recognize the decline of Americans' compromising spirit and the rise of confrontational moral imperatives, wisely avoided repeating his predecessor's dire pronouncements. [my emphasis]The politics of the slavery issue were changing in ways that Jefferson may well have misunderstood. He interpreted the antislavery proposal that initiated the Missouri crisis as a cynical political ploy on the behalf of monarchist-inclined Federalist types.
Politics is politics, so it would be truly remarkable if the antislavery advocates in Congress didn't pay attention to the effect of such proposals on their own political fortunes. But however cynical the individual politician using the issue, the issue wouldn't lend itself to cynical usage if there weren't some support among their public for it.
The institution of slavery and the attitudes of white supremacy were also evolving rapidly. At the beginning of the 19th century, the defenders of slavery typically justified the Peculiar Institution as a civilizing force, lifting the African slaves to a higher level of civilization. This ideology obviously had more than a little cynicism in it, too. William Freehling calls that the "necessary evil" defense of slavery. (The Road to Disunion, Vol. 2: Secessionists Triumphant, 1854-1861; 2007) Over time, that justification of slavery fell out of favor in the Lower South, although it continued to be used more often in the Upper South. The latter approach grew and intensified as slavery began to come under more intense challenge.
The new, activist Abolitionist movement and hardening Southern commitment to slavery were making the gradual abolition process no longer feasible in practice. In retrospect, the Missouri crisis symbolizes that shift in practical possibilities.