Shelby Foote had an interesting observation about the odds the South faced:
“I think that the North fought that war with one hand behind its back. At the same time the war was going on, the Homestead act was being passed, all these marvelous inventions were going on... If there had been more Southern victories, and a lot more, the North simply would have brought that other hand out from behind its back. I don’t think the South ever had a chance to win that War. “
Not sure I agree with this entirely. I believe Grant going East sealed the deal. That and Sherman taking Atlanta. Without Grant and Sherman Lincoln probably loses the 1864 election. That would have almost certainly resulted in a negotiated end to hostilities with the South leaving the Union.
Lincoln, Grant, and Sherman were the great trifecta. Before Grant there was chaos. Grant likened Union strategy to a balky mule team, no two pulling in the same way. Grant made sure everyone was on the same page moving toward a common center. He brought the full weight of the North to bear on the very heart of the Confederacy, Lee’s Army of Northern Virginia.
I agree the Union might easily have lost the war.
Democrat generals like McaClellan and shortsighted generals like Hallack could have turned Northerners against the war and so lost it.