Reagan and Mr. Bush didn’t win because they drew more conservatives. They won because they performed well with independents and moderates. Reagan beat Jimmy Carter among independents by 25 points, while Mr. McCain lost that group by eight points. The Gipper prevailed among moderates by six points, while Mr. Romney lost them by 15.

What these numbers show is that moderate candidates aren’t automatic winners any more than are conservative candidates. John McCain has made a career-long fetish of cultivating his maverick reputation, but he performed far more poorly among independent voters than did the much more partisan Reagan. Mitt Romney won the Massachusetts governorship as a moderate and adopted a centrist tone in his second presidential campaign, but he did 21 points worse among voters who called themselves “moderate” than Reagan did.

Americans vote for talented politicians with winning personalities, and they display no longstanding ideological voting pattern. They embrace charismatic candidates, whether conservative (Reagan), “compassionate conservative” (Bush), moderate (Ike), neo-liberal (Clinton), or progressive (Obama).

This historical record suggests that a gifted, powerfully persuasive conservative—like Marco Rubio, Paul Ryan, Bobby Jindal or Chris Christie—could plausibly win in 2016, just as a dull, inauthentic moderate would probably lose. Recent experience reaffirms the fact that the American people don’t automatically award certain victory or inevitable defeat based on ideological outlook, despite cherished conservative legends to the contrary.