“Why would Congress go along with Lincoln’s political shenanigans and prop up a President that few had committed to support in the 1864 election? “
I don’t know the answer to your question.
And I don’t know why Congress went along with Lincoln’s decision to kill 600,000 Americans.
You keep making this sound like it was Lincoln's unilateral decision. History is far more complex than that. No accountability to the southern leadership? What exactly did they achieve for the sacrifice of almost an entire generation of young men? What did they think they were going to obtain in defending an institution which is morally indefensible, benefited mainly the elite of southern culture, and which even lost-cause defenders admit was doomed to extinction in a short time anyway? You're looking at the wrong political leaders to affix blame.
With such comments jeffersondem demonstrates yourself to be a true Democrat -- always blaming others for their own actions.
It's equivalent to our modern Democrats caterwauling that "Republicans shut down the government!" when in reality, it's always Democrats who actually cause it.
But their success in blaming Republicans has driven them to repeat the claim as often as possible.
And now like a true Democrat, jeffersondem blames Republicans for the war Democrats provoked, started, declared and waged until final defeat and unconditional surrender.
[sigh} It's what real Democrats do, sort of in their political DNA.