The law was a mute academic point with Lincoln. He did not require any legal authority to suspend habeous corpus and he did not ask Congress for permission to starve and withhold medicine from Confederate POW's. "To Die in Chicago:Confederate Prisoners at Camp Douglas 1862-1865" is an excellent source of information. If necessary, I will comb over the 369 pages and show it.

And Pam is exactly right about citizens attempting to feed the Confederates. In Chicago, there was a lot of humanitarian aid from citizens.