[FLT-bird]

For slaveholders, once Lincoln was elected, that provision was like a dagger pointed at them and slavery.

Why would that be? Lincoln orchestrated passage of the Corwin Amendment and endorsed it in his first inaugural address. He also offered strengthened fugitive slave laws. What he did not offer was any abatement of the Morrill Tariff.

[Rockingham]

The Morrill tariff was not a significant cause of secession. Slavery was the cause. Lincoln did not orchestrate the Corwin amendment. At the time, abolitionists were not a majority sentiment.