As Ramesh points out below, Bill Rusher makes a good case in favor of Reagan’s election in 1968, but there is a good case against it. A few observations.
First, Reagan came closer to derailing Nixon’s first-ballot nomination that is generally recognized. Lots of southern delegations wanted to go for him and had to be kept in line for Nixon (chiefly by Strom Thurmond) through strong-arm tactics and brutal use of the rules. Had it gone to a second ballot, it would have probably come down to Reagan v. Nelson Rockefeller, and Reagan would probably have won.
However, Reagan himself told several people on the way back to California that he was relieved not to have won the nomination, because he didn’t think he was ready to be president. The man had a sense of destiny and providence about himself that should not be discounted. And, when recalling how badly the early weeks of the fall 1980 campaign went for Reagan, one wonders how he would have fared in 1968, before a lot of the adjunct conservative infrastructure was in place to help him and the conservative cause against the hostile media, etc.
Finally, there is the question of whether, had Reagan won in 1968, he would have been able to govern effectively. Nixon had no coattails, and faced a hostile Congress. No doubt Reagan would have got a lot of big things right that Rusher mentions, but just as easily it could have been a exercise in extreme frustration and political division worse than what we see with Bush right now. Reagan’s coattails in the 1980 election were very important to his forward momentum in his first term.
Then there is the problem of personnel: even in 1981 the Reagan administration had trouble finding enough qualified conservatives for major and minor appointments. The bench was even shorter in 1968. Jeane Kirkpatrick would not have been available, or all the other neo-conservative Democrats like Max Kampelman (who would have been Humphrey’s Secretary of State) who played important roles in the Reagan administration.
I conclude that neither Reagan nor the conservative movement were ready for prime time in 1968.