Des Moines, Iowa ? Want to know how Americans will vote next Election Day? Watch what they do the prior weekend.

If they attend religious services regularly, they probably will vote Republican by a 2-1 margin. If they never go, they likely will vote Democratic by a 2-1 margin.

This relatively new fault line in American life is a major reason that the country is politically polarized. And the division over religion and politics is likely to continue in 2004.

A new poll by the nonpartisan Pew Research Center For The People & The Press this fall confirmed that the gap remains; voters who frequently attend religious services tilt 63-37 percent to Bush and those who never attend lean 62-38 percent toward Democrats.

“We now have the widest gap we have ever had between Republicans and Democrats,” said Andy Kohut, the director of the Pew survey.

“It’s the most powerful predictor of party ID and partisan voting intention,” said Thomas Mann, a political scholar at the Brookings Institution, a center-left Washington research center.

President Bush is a churchgoing Christian who often mixes theology with public policies ranging from the war on terrorism to a ban on a specific type of late-term abortion. By contrast, most leading Democratic candidates for president keep their campaigns secular, seldom mentioning God, religion or church.

The most notable exception among top-tier candidates is Sen. Joseph Lieberman of Connecticut, a Jew who frequently invokes God, casts policy issues in moral terms and refuses to campaign on the Sabbath.

The Rev. Al Sharpton is religious too, of course, but polls show he’s favored by fewer than 1 percent of likely Democratic voters in New Hampshire, the first primary state.

In contrast, the front-runner for the Democratic nomination, former Vermont Gov. Howard Dean, said recently that he prayed privately, but quit being an Episcopalian in a dispute with his parish over a bike path, recently linked God with guns and gays in a list of issues that shouldn’t influence voting and doesn’t regularly attend church. Nor do most of his chief rivals.

It wasn’t always so. Most Democratic candidates through the 20th century were openly religious. Born-again Christian Jimmy Carter ran in 1976 as much a moral messenger (“I will never lie to you”) as a champion of the Democratic policy agenda. Bill Clinton could quote the Bible as readily as the party platform.

Voters weren’t split by the frequency of their visits to church, synagogue or mosque until recently. The gap became clear in the 2000 election between Bush and Al Gore. Voters who attended services went for Bush by a margin of 2-1. Those who never went to services went for Gore by the same margin.