The Republican Party has been plagued for almost 50 years by the "lesson" they learned in Barry Goldwater's defeat.
Republican strategerists (as Rush Limbaugh calls them), learned a powerful lesson from the Goldwater debacle of 1964. Since Lyndon Johnson trounced Barry in the election, just one year after the assassination of the charismatic John Kennedy, Republicans came to believe that "extremist" candidates were a bad idea. They decided that the trick to winning an election was, to attract moderates, the vast so-called silent majority. Surely that must be what they did wrong when they ran Barry Goldwater.
What They Missed:
In 1964, the nation was polarized. Democrats were playing with social engineering. Republicans were reacting strongly to what they saw as creeping communism. The nation had been stunned by the murder of a popular young president. The Republicans could have run Jesus and still would have lost that election. The sides were clearly defined. The lines clearly drawn. The election came down to which way the moderates would swing. With the Kennedy assassination, the middle mass of the voting public swung powerfully to the Democrats. To draw any conclusions about how to win (or lose) presidential elections from the 1964 election is a mistake. The only thing you can say for sure is that the party in power should have its current president assassinated just before the election if you want to win for sure. Look how fast Lyndon Johnson fell from grace once the impact of his policies began to be felt out in the real world.
What Else They Missed:
The Goldwater campaign had one bright spot. It launched the political career of arguably the most influential Republican of the the past century. Ronald Reagan's famous "Last Stand on Earth" speech was the high point of the 1964 convention. It kind of annoyed Goldwater because up beside Ronald Reagan, Barry looked kind of lame. Listen to this brilliant speech again. Consider it a political recharge: