The survey highlighted increased frustrations with politicians making compromises on such hot issues as abortion and gay rights.
At the same time, those polled said they were growing bolder about pushing their beliefs on others - even at the risk of offending someone.
The trends could indicate that religion has become "more prominent in American discourse ... more salient", according to Ruth Wooden, president of Public Agenda, a nonpartisan research organisation which released the survey.
It could also indicate "more polarised political thinking. There do not seem to be very many voices arguing for compromise today", she said in an interview.
"It could be that more religious voices feel under siege, pinned against the wall by cultural developments. They may feel more emboldened as a result."
The findings came from a telephone survey of 1507 adults made in 2000 and a second similar survey of 1004 adults done during the summer of 2004 that tracked the same issues. It had a margin of error of plus or minus three percentage points.
Bush adviser Carl Rove (C)
courted the Christian vote
Those surveyed were nearly all Christians, not by design but because the sample reflected the make-up of the population, the group said. A 2002 Pew Research Council survey found that 82% of the US populace considered itself to be Christian, while 10% identified with no religious group.
On the question of whether elected officials should set their convictions aside to get results in government, 84% agreed in 2000. However, four years later that had dropped to 74%. There was a sharper decline on the same question among weekly church-goers from 82% in the first survey to 63% in the second.
About 40% of Americans claim to be weekly church-goers, according to Corwin Smidt, director of the Henry Institute for the Study of Christianity and Politics at Calvin College in Michigan. Some surveys have placed the figure at 25%.
Compromises less likely
In the survey, 32% of those who attended church once a week said they were willing to compromise on abortion issues - a 19-point drop in four years. Among the same group the
question of compromising beliefs on gay rights was acceptable to only 39%, down 18 points from 2000.
The poll also found that 37% overall felt that deeply religious people should be careful not to offend anyone when they "spread the word of God", a decline from 46% four years earlier.
The number of those who felt that committed faithful should spread the word "whenever they can" rose to 41%, up six points.
On another issue, the survey found little change in opinion on whether the US political system can handle greater interaction between religion and politics.
Asked if there was a threat if religious leaders and groups got a lot more involved in politics, 63% in 2000 and 61% in 2004 said the system could "easily handle" it. But the remainder continue to believe the system would be threatened.