The founders were very worried that if parties developed in America, you might have something like the modern Italian system, where you have 20 different parties that divide Congress and the country and can't govern.

What if we had a culture that prevented these presidents from being courageous? And I worry now that we have a system that makes it very hard to choose people who would make the same courage choice as our great presidents. And I guess what I would say is, in this next campaign, take a look at the people who are running. If they don't remind you of the great presidents, do not vote for them.

So the result was that as one approached a political convention for most of the 19th century and for most of the 20th century until the 1960's, part of the drama was the fact that you didn't know ultimately who was going to be the nominee at the end of that convention week.

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.

The original thing that fascinated me most was why we expect leaders, and especially presidents, at times to destroy themselves - and that's a sign of being a good leader or a good president. We usually don't expect that of almost anyone else in any profession, in particular, in public life.

So if 1960 had occurred under the old convention system, Kennedy would have had a very hard time getting the Democratic nomination because he would have been rejected by all those people who had worked with him in Washington.

Legacy is what a president does that affects later generations.