Washington is atwitter. Mitt Romney will give a "JFK speech" Thursday accounting for his Mormonism the way then-Sen. John F. Kennedy dealt with his Catholicism in 1960. Political junkies just love Kennedy nostalgia. So profound is the Kennedy cargo cult that Michael Dukakis - who was as much a reincarnation of JFK as Weird Al Yankovic is of Frank Sinatra - tapped Texas Sen. Lloyd Bentsen as his 1988 running mate because he believed it would revive the "Boston-Austin" axis of the JFK-LBJ ticket. Recalling the electricity and verve of that Democratic ticket, who among us can deny Dukakis' wisdom?

Such are the dangers of political nostalgia, which often drives candidates to repeat history as farce.

Until recently, Romney was rightly reluctant to give a "JFK speech." He seemed to understand that JFK's 1960 address to the Greater Houston Ministerial Association has become the stuff of legend and any effort to match it would come up short. "I probably could never do something that would compare to what John F. Kennedy did," Romney said in October. "His was a masterpiece in American political history."

Well, now the former Massachusetts governor is going to talk about "faith in America," and in Texas no less. We don't know what he'll say, but it's easy to guess why he's saying it: Mike Huckabee. The Southern Baptist minister and former Arkansas governor is leading in Iowa polls, scuttling Romney's plan to use a victory there as a springboard to the nomination. Huckabee's charm, skill and socially conservative record explain much of his success. And Romney's Olympian hair, hypnotic teeth, squishy record and yacht-salesman demeanor are all important factors in why he can't seal the deal with some Iowa voters.

But there's another factor: Romney's heresy. I don't mean this in a pejorative sense, though others do. Mormonism is seen as a non-Christian cult by many conservative Christians, and a Romney nomination or presidency, they fear (I don't), would serve to advance the mainstreaming of Mormonism. In fairness, the Christian right is no monolith, and Romney has many religious conservatives in his corner. If Huckabee weren't in the race, he'd have more.

Still, Romney is marching into a theological headwind the other candidates aren't. It's not a question of "Mormon public policy." Some of the most effective conservatives in Washington are Mormons. What rankles is the widespread characterization - mischaracterization in their eyes - of Mormonism as merely another denomination of Christianity. Phrases like "a stronghold of Satan's" (applied to Utah) and "false prophecy" (applied to the "cult") get bandied about in some circles. Others are coldly analytical; a Mormon president, they correctly adduce, would only aid the Church of Jesus Christ of Latter-day Saints' remarkable success at proselytizing at home and abroad.

How can Romney address this concern? It's not like he could - or should - say he's no Mormon role model. And talking theology at all is only likely to exacerbate his problem with the voters who care about it, i.e. the voters he needs.

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.