Buchanan led to the election of Lincoln and "resolution" of the problem that Buchanan failed to solve and which he probably made worse.
I would argue that Obama (who, incidentally, may be homosexual) fumbled his presidency and supported Socialism and the concept of slavery under a one world government.
Obama's tenure led us to Trump who, in my opinion, will be seen as greater than Lincoln.
As Mark Twain said: "History doesn't repeat, but it does rhyme." This is a good example of that.
“Obama’s tenure led us to Trump who, in my opinion, will be seen as greater than Lincoln.”
Lincoln was never the great president that he is made out to be. I think Trump may wind up making Lincoln look like a slub. Lincoln was a great wordsmith.