WASHINGTON (By

Candidates have long recognized religious affiliation as a significant factor in American elections. In the 1940s, for example, Catholics tended to vote Democratic and mainline Protestants tended to vote Republican. A similar gap now exists between white evangelical Protestants, who are strongly Republican, and black Protestants, who are strongly Democratic.

In the last three decades, however, a second religion gap has appeared, this one based on frequency of attendance at worship services. Voters who report attending religious services at least once a week — regardless of religious affiliation — tend to vote more Republican. Those who say they attend religious services less often (termed "less observant" for the purpose of this analysis) tend to vote more Democratic.

The Religion Gaps in 2004

In the 2004 presidential election, exit polling by the National Election Pool found that religious affiliation and frequency of attendance at worship services had a larger impact than many other, better-known factors, including the "gender gap" between men and women and the "class gap" between the most and least affluent voters.

The religion gap based on attendance, although not as stark as the affiliation gap, is also significant. Within all the major religious traditions surveyed, people who attended religious services at least once a week voted more Republican than did their less-observant counterparts within the same religious affiliation.

Among evangelical Protestants, for example, Bush received support from 82% of those who attended services at least weekly, compared with support from 72% of those who attended services less frequently (a gap of 10 percentage points). Comparing evangelical Protestants' support for Bush with that for Kerry, Bush held a 44-point advantage over Kerry among evangelical Protestants who attended services less than weekly. However, the advantage for Bush increased to 64 points among evangelical Protestants who attended services at least weekly.

The pattern also held true within religious traditions that generally supported Kerry. Among black Protestants, Kerry received greater support from those who attended services less than once a week than from those who attended services weekly or more often (92% vs. 83%, a nine-percentage-point gap). Comparing black Protestants' support for Kerry with that for Bush, Kerry held an 84-point advantage among those who attended services less than weekly. However, the advantage decreased to 66 points among black Protestants who attended services at least once a week.

The gap based on frequency of attendance at worship services also is apparent even within religious traditions that split their votes somewhat more equally between the two candidates. For example, among non-Latino Catholics, Bush received much greater support than did Kerry from those who attended services at least weekly (a 24-point gap), while Bush's support among those who attended services less than once a week was not as overwhelming (a six-point gap).

No Religious Majority at the Ballot Box

An analysis of religion-based voting patterns shows that no simple "religious majority" exists in the American electorate. In the 2004 presidential election, for example, weekly attending evangelical Protestants and less-observant mainline Protestants accounted for the largest portions of the popular vote (each at 14%), and most religious constituencies accounted for less than 10%. As a result, presidential campaigns are forced to assemble broad coalitions encompassing many religious communities, and the two religion gaps help define the composition of these coalitions.

In 2004 the most important group in Bush's re-election coalition was evangelical Protestants, who accounted for a third of his total votes on Election Day. He also obtained modest but crucial support from members of other religious groups, such as the unaffiliated, who on balance voted Democratic.

Kerry drew strong support from religiously unaffiliated voters (about one-in-five of his total votes) and a diverse array of other groups, including black Protestants and non-Latino Catholics. He also won some votes from largely Republican-leaning groups, including evangelical Protestants.

What about 2008?

There is some preliminary evidence that the affiliation gap again is at work in the lead-up to the 2008 presidential election.

A January 2007 Pew survey, for example, asked people if they would most like to vote for a conservative Republican candidate, a moderate Republican candidate, a moderate Democratic candidate or a liberal Democratic candidate for president in 2008. As in 2004, religious affiliation appears to be an important factor in the responses: Evangelical Protestants were the most likely to back a Republican presidential candidate. Conversely, the lowest level of support for a Republican came from unaffiliated voters and a composite of religious groups — including black Protestants — that were too small to break out individually in the Pew survey. Falling in between were mainline Protestants and non-Latino Catholics; their support for a Republican was lower than that of evangelical Protestants but higher than that of the unaffiliated.

The gap based on frequency of attendance at worship services also may be at work. Regardless of affiliation, weekly attenders were more likely to back a Republican candidate than were the less observant. The survey also showed, however, that many of the constituencies that backed Bush in 2004, including less-observant evangelical Protestants, are more likely to support a Democratic candidate in 2008. In addition, the Democrats are attracting even stronger support from religious constituencies that backed Kerry in 2004. For example, 38% of weekly attending non-Latino Catholics voted for Kerry in 2004, but 52% say they would "like to vote" for a Democrat in 2008.

These early preferences must be viewed with caution, however. It is possible, for instance, that the survey results may simply reflect President Bush's low popularity at the time the survey was conducted. Moreover, the survey questions did not mention specific candidates for either party.