Polarization within religions is relatively new, the report said, and Bliss Institute director John Green said this development may make it more difficult to forge coalitions on social issues.

Mainline Protestants, who traditionally lean Republican, divided their votes between Bush and Kerry, giving the Democrat the highest level of support from that area in recent times, the report said.

Once a bedrock of Democratic support, non-Latino Catholics last year gave more than half of their vote to Bush. Green also found more support than four years earlier from black Protestants and Latino Catholics.

He said Bush captured votes from middle-of-the-road Christians, especially Catholics, people the Democrats need to court in the future.

Green told Reuters the findings indicate Democrats have their work cut out if they want to win back the White House four years from now.

"These numbers reinforce the notion that this was (an election) where both sides did a good job of getting out their core voters. The problem for the Democrats is that the result still favored the Republicans," he said.

But "the polarization may well make it more difficult to reach the centrists," he said, especially when it comes to making compromises on social issues that will appeal to entire spectrums of the faithful.

"The strong support from traditionalists (conservatives) gives the GOP a leg up in 2008. They can't just depend upon them because traditionalists are not numerous enough. But it provides the GOP with a strong base to which they can add more moderate groups," he said.

At the same time, he said the Democrats' base of more progressive faithful and those who are not affiliated with any religion "is smaller and more difficult to mobilize, so they have to work doubly hard."

The fourth annual survey, conducted by the Pew Forum on Religion and Public Life, covered a representative sample of 2,730 Americans who were contacted in the spring of 2004 and again in the weeks after the November election. It had an error margin of 2.5 points plus or minus.

Among other things it found:

--Economic and foreign policy issues overall were more important for voters than social issues such as abortion and same-sex marriage. But social issues were more important to those who voted for Bush, while economic issues motivated Kerry voters.

--Kerry made inroads into voters who were not affiliated with major religions, but they were not moved to vote at any higher level than they did in 2000.

--Bush's biggest gain in terms of religious affiliation came among Protestant Latinos, a relatively small segment of the population, who moved from the Democratic to the Republican camp in 2004 compared to 2000.

--In the end only 21 percent of voters said their faith was more important than other factors in casting their vote and another 26 percent said it was about as important as anything else in their decision -- a combined total of less than half.

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