how did john c. calhoun say the Union could be saved?

Answer 1

Parallel govts., with dual presidents to protect the interests of each section. He was out of his mind.

Answer 2

Mostly by the North giving an excess of power to the south so they could continue with their economic farce of slavery. He demanded that southern states be given more representatives in the house to even thigs out with the more populous north, that there be a dual presidency (one from the north, the other from the south) and that states should have to right to not obey laws and tarriffs passed by congress, which was unconstitutional.