This southron canard gets repeated over and over and over until it is accepted as gospel, just like the ridiculous claim that the south paid 85% of the total tariffs. The actual fact is that, far from banning imports, the confederate constitution actually protected imports. Article I, section 9:
The importation of negroes of the African race from any foreign country other than the slaveholding States or Territories of the United States of America, is hereby forbidden; and Congress is required to pass such laws as shall effectually prevent the same.
Yep, and Chase's actions 8 years earlier did nothing to influence his self serving decision in '69. < /sarcasm> The fact is that the statement in the Confederate Constitution went further towards ending slavery altogether than anything in the US Constitution. It further appeased the small, minute, non existant Abolitionist Party in the union by stating that no slaves would be accepted from union states. The border states knew that slavery was dying out over simple cost. Within 20-30 years it would have died off altogether. Stephens as much said this in his discussion with lincoln (root,pig, or perish conversation. Surely you remember that Non). Instead ol' abe decided that 600,000 men had to die, the nation go into debt 100 times what it was in '61, and his all glorious Hamiltonian Empire just HAD to be built