Americans are increasingly uneasy with the mingling of religion and politics, according to a poll released Wednesday by the Pew Research Center, in the midst of a campaign season punctuated by tussles over the role of faith in the public square.

Back in 2001, when Pew first asked the question, just 12 percent of Americans complained that their politicians talked too much about religion.

That number has risen steadily ever since and hit a record high in the new poll: 38 percent of Americans, including 24 percent of Republicans, now say their political leaders are overdoing it with their expressions of faith and prayer. The Pew study said that between 1996 and 2006 the balance of opinion on this question consistently tilted in the opposite direction - favoring more church input on political and social issues.

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And more Americans than ever, 54 percent, believe churches should keep out of politics. That's up from 43 percent in 1996, according to the Pew Research Center.

The national poll of 1,503 adults, which has a margin of error of 3 percentage points, was conducted in early March, as the US Conference of Catholic Bishops was ramping up its vigorous campaign against a new federal mandate requiring all insurance companies to provide free birth control.

The bishops continue to press that fight. Just last week, they issued a statement declaring they were "strongly unified and intensely focused" on battling the contraception mandate.

A leading voice in that campaign, Bishop William E. Lori of Bridgeport, Connecticut, this week was promoted to Archbishop of Baltimore by Pope Benedict XVI.

Peter Steinfels, co-director of the Center on Religion and Culture at Fordham University, said Americans have generally tolerated and even encouraged religious leaders to speak out on broad political issues, including capital punishment, immigration and poverty.

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But Americans have long been uncomfortable with religious leaders directly involved in partisan campaigns, he said.

In recent years, most notably in the birth control battle, that line has been blurred, Steinfels said - which may account for the growing unease on display in the Pew poll.

"Religious leaders ought to be worried," Steinfels said. "We're seeing Americans becoming more skeptical" about the propriety of religious involvement in politics.

The bishops have sought to portray the contraceptive mandate as one prong of a broad attack on religion by state and federal authorities. The leading Republican presidential candidates have echoed that rhetoric on the campaign trail, accusing the Obama Administration of declaring war on religious freedom.

The Pew poll found evidence that argument is resonating with Catholics. Roughly one in four US voters is Catholic and they are a crucial swing vote in several states pivotal to the 2012 presidential election, like Ohio, Michigan and Pennsylvania.

The poll found 25 percent of Catholics perceive the Obama administration as unfriendly to religion, up from 15 percent in a Pew poll taken in August of 2009.

The increase is even sharper among white Catholics, jumping to 31 percent from 17 percent, Pew found.

Among the public overall, 23 percent describe the Obama administration as unfriendly to religion, up from 17 percent in 2009. But another recent poll suggests the "war on religion" argument isn't gaining traction with most adults.

A national survey conducted this month by the Public Religion Research Institute found a majority of Americans, 56 percent, do not believe religious liberty is under siege.

Republicans, senior citizens and white evangelicals were most likely to see a looming threat to religious freedom.

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(Reporting By Stephanie Simon; editing by Marilyn W. Thompson and Todd Eastham)

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