Doyle, the problem with that argument is that southern leaders were delighted to make slavery a "federal" issue when it suited their purpose - just look at the Fugitive Slave Act, which made the recapture of slaves a prerogative of federal authorities. They had no hesitation then in using the feds to coerce the actions of others. As usual, we only have to look at whose ox is being gored.

Besides, when before the war did the federal government directly regulate, or interfere with, slavery in the states where it was then legal?