It would be overly simplistic to state that candidates such as Romney, Bob Dole, and Sen. John McCain lose because their candidacies discourage conservatives.

The deeper issue is that when the Republican nominee is somebody who conservatives are suspicious of, the nominee has to spend the whole primary trying to convince conservatives that he or she agrees with them, and then the general election constantly reassuring them that he or she isn’t going to abandon the right just because the nomination has been sewn up. This leads to incoherent campaign messaging…

When base voters implicitly trust a candidate, they’re more likely to give that candidate the benefit of the doubt when he or she tries to communicate a message to appeal to the broader electorate, because they assume that deep down that candidate “gets it” and is “one of us.” A candidate who is constantly having to prove something to the base — from the declaration of candidacy to the waning hours of Election Day — is guaranteed to lose.