In recent presidential history, Republicans have swamped Democrats among voters who regularly attend worship services - and in the last two nail-biters they provided more than the margin of victory.
But a new poll out is the latest to suggest that this November will not be a repeat.
The Barna Group, which tracks faith groups, said Democrat Barack Obama is leading Republican John McCain 43 percent to 34 percent.
Obama's campaign Tuesday highlighted the findings that, of the 19 faith groups tracked in the poll, McCain is only leading among evangelicals. Still, like other national polls, it shows the race appears to be tightening. Obama led 50 percent to 35 percent in the same poll in early June.
McCain has long been viewed with some suspicion by the Christian right, and he has not solidified support among those leaders and voters. He badly needs to do so to win in November.
The Pew Research Center for the People & the Press compiled exit poll data showing that in 2004, President Bush beat Democrat John F. Kerry 58 percent to 41 percent among voters who said they attended services once a week - and 64 percent to 35 percent among those worshiping more than once a week. In 2000, Bush defeated Democrat Al Gore with similar margins. In both elections, those attending services at least once a week made up more than 40 percent of all voters.