On this one point alone, I think Loewen got it right. Lincoln definitely did not go to war to end slavery. Although many abolitionists pressured Lincoln to eradicate slavery, he was hesitant to make any commitment.
One reason was that the abolitionists themselves could not agree on a single course of action. Many wanted to round up all the blacks – slaves or not – and ship them back to Africa. Personally, even Lincoln sided with the notion of shipping them all “back” even though all those currently alive had been born here. He could think of no other graceful solution to the problem.
A few of the group wanted to free the slaves, give them land to settle on and give them an education. This did not go over as well because of the prevailing wisdom that the blacks, like the Native Americans, had no soul nor the capacity to be educated.
So, though Lincoln had no great love of slavery, we’ll never know if he would have shipped them back to Africa. We’ll never know how he would have handled the Reconstruction phase of American history because someone removed him from this plane of existence.