The Founding Fathers would be sorry to see that America had become so divided and factionalized.

A lot of it was, you know, you look for moments where, for instance, we were dependent on Abraham Lincoln making sure that the slaves were freed or John Kennedy bringing civil rights, or the first one I wrote about, George Washington trying to stop the British from invading and ending this country before it even began. Those were turning points where, if you had not had a president stepping up to the plate, if there wasn't a story like that, we would not be here.

As parties began to develop around the turn of the 19th century, you had party nominees for President nominated in caucuses made up of party members in Congress.

I'm defining [presidential courage] pretty narrowly. It's not only taking a big political risk but it's also the risk that in the hindsight of history, people think it's wise.

First of all, there's no mention of political parties in the Constitution, so you begin American history with not only no political conventions but also no parties.

Then you get to the last half of the 20th century, Americans are getting very skeptical about their leaders and their institutions, and another place that is affected is parties and conventions.

Under the system that we now have to nominate presidential candidates, for instance, I would prefer that we have a system that is closer to, say, the one we had in the 1960s.