In 1960, Catholics numbered somewhere between a quarter and a third of the electorate, politically dominating some states. Today, Mormons amount to roughly 2 percent, and most are concentrated in or around Utah. In many primary contests, Kennedy's Catholicism was an asset. In Wisconsin's open primary, many GOP Catholics crossed party lines, securing Kennedy's victory over Hubert Humphrey. Mormon Democrats for Romney are unlikely to have a similar impact.

Also, in 1960, Kennedy tackled his version of the "religion issue" head-on in the primaries but delivered "The Speech" only after securing the nomination. He pledged to uphold a severe separation of church and state.

So far, Romney's stance has been much more akin to that of 1928 Democratic nominee Al Smith, who largely refused to discuss his faith. Smith's loss was a complicated affair, with anti-Catholic bigotry part of the equation. But his defeat also owed to the fact that he opposed Prohibition (God bless him) - alleged proof Smith that was a pawn of the anti-Prohibition Catholic Church.

There's nothing like that going on today. Indeed, the people Romney needs to win over believe that there should be more, not less, room for religion in public life. He won't gain votes by calling them bigots - no matter how gently - either. And the last thing Romney can afford to do is backpedal on his religious faith. That would be a flip-flop too far.

What he needs to do is reject the Kennedy comparison entirely and sell his candidacy on its own merits. Electability is still more important than theology to most Republicans, and that's where he should take his stand. Instead, he's heading to Texas to play a game he can't win.