ALLAN LICHTMAN: I think his legacy is absolutely split down the middle. On the one hand, one can say all kinds of positive things. He might have saved us from a great depression and a financial collapse. Saved the automobile industry, put forward regulations designed to prevent another meltdown. Of course, passed the Affordable Care Act, something that's -- medical reform -- that's eluded presidents for decades. He might have averted a nuclear arms race in the Middle East. He's opened up Cuba.

On the other hand, he has forgotten what the great iconic Democratic president Franklin Roosevelt always taught, and that is, you not only have to be an innovator of policy, have you to be a party-builder, and that's where Obama has fallen down. During the Obama years, the Republicans have played hardball and Obama and the Democrats have played whiffle ball.

Obama came in, the Democrats had the presidency, the House and the Senate. What do they have today? Nothing.

The Republicans control the presidency, the House and the Senate. They'll have the Supreme Court. They have most governorships, most state legislatures. As Lyndon Johnson, who was, of course, a great politician, once said, you have to have the election certificate if you're going to be a statesman. And that's why the Obama legacy is so divided and is going to be a subject of enormous controversy among my brethren, the historians, for a long time to come.