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.
Michael BeschlossSo 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.
Michael BeschlossFirst 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.
Michael Beschloss