I'll address any subject I like.
You were saying that Lincoln was a political opportunist. Donald's work suggests that Lincoln was a man of principles that could not be shaken. That is a fair interpretation.
More Donald:
Donald states (about Lincoln in August of 1864), "...Had he failed to to insist on abolition as a condition for peace negotiations, he explained, he would be guilty of treachery to the hundreds of thousands of African-Americans who had 'come bodily over from the rebel side to ours.' Such betrayal could not 'escape the curses of Heaven, or of any good man.'
...this was interpreted the next day in the New York Times thusly:
"Mr. Lincoln did say that he receive and consider propositions for peace...,if. they embraced the integrity of the Union and the abandonment of Slavery. But he did not say that he would not receive them unless they embraced both these conditions."
Lincoln further said:
"There have been men who have proposed to me to return to slavery the black warriors of Port Hudson & Olustee to their masters to conciliate the South. I should be damned in time & in eternity for so doing. The world shall know that I will keep my faith to friends & enemies, come what will."
Now, Lincoln made these statements in late summer 1864 -- when he seriously thought the 1864 election could not be won.
He was a man of principle; the record shows that much.
Walt