Ellis Henican: Would it be so bad if presidents let faith rule their actions?

Religious interference? Actually, John Kennedy probably could have used a little more religious interference. If he'd only listened to the dictates of his church, the Catholic president might have kept his distance from the likes of Marilyn Monroe.

But no. He believed his own flowery rhetoric about the separation of church and state. America was a nation "where no Catholic prelate would tell the president, should he be a Catholic, how to act."

What a wasted opportunity. In the absence of political guidance from Rome, Kennedy got all entangled in female trouble. Marilyn. Judith Exner. God only knows who else.

This all comes up, of course, because of Mitt Romney and his big speech Thursday, wherein the former Massachusetts governor tried to calm Republican fears of nominating a Mormon for president.

"Let me assure you that no authorities of my church, or of any other church for that matter, will ever exert influence on presidential decisions," Romney said at the George Bush Presidential Library on the campus of Texas A&M University. Very Kennedy-esque.

But here's the twist in the story. Lots of recent presidents could have been saved from their worst instincts by their faiths, had they only followed them more religiously. Bill Clinton. Richard Nixon. Ronald Reagan.

In America, we demand that our leaders have religious faith. No atheists or agnostics need apply. And we demand they speak publicly about their beliefs.

At the same time, we aren't especially insistent that they practice what they preach.