There is a big difference between a President, who was (according to the Southern Cabal), acting tyrannically and not getting impeached by the Congress (its constitutional responsiblity) and trying a traitor who could no longer hurt the nation he had betrayed.
Charity towards all, Malice towards none
Yeah, the Lincoln congress was real big on constitutional responsibility. You must've skipped nolu chan's post concerning ratification of the 14th. Perhaps you might notice that roughly half the country was denied suffrage in the Senate. Please, continue to lecture us on the constitutional responsibilities of the Congress during the 1860s (and '70s).