Michael Beschloss

The Founders deliberately limited presidential authority.

Oftentimes during the period in which conventions really did business, you had situations where the delegates were divided and you would have ballot after ballot before there was a final nominee.

From the beginning of the presidential nominating conventions in the 1830's really through the 1950's, you had conventions that actually did real business.

During his last 18 months in office, Eisenhower flew to Asia, Europe, and Latin America and deployed his war hero's popularity to seek new friends for America while trying to improve relations with Moscow. By the time Ike left office, most Americans had forgotten their anger over losing the space race to the Soviets.

Too few presidents have steeped themselves not just in Lincoln's words but his deeds, which is why Obama's acquaintance with the great man is so compelling - especially since, like President-elect Lincoln, Obama will take office at a perilous time.

Historians sometimes view presidents very differently from the way the public did at the time. Sometimes they don't.

Historians often find important decisions few knew were important at the time.

Even if you have presidents like FDR dealing with someone like Stalin, with whom he didn't exactly all the time disagree... He wasn't always in lockstep saying Stalin was wonderful all the time. Donald Trump never criticizes Putin.

There is a great overlap of tragedy that played out through the generations of the Lincolns. That, coupled with the idea that many people consider Lincoln our greatest president ever and the fact that he was also a man assassinated at the age of 56 and had a widow with mental problems is what makes it all so fascinating.

You have had presidential candidates over the last 30 years who would have had a very hard time getting nominated under the old system. One example is John Kennedy.

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.

Reagan's defense buildup and SDI, so ridiculed at the time, pressed Gorbachev, while his economy was collapsing, to make arms deals and improve relations with the West, which contributed to the unraveling of his empire.