The sermons, on what is called Pulpit Freedom Sunday, essentially represent a form of biblical bait, an effort by some churches to goad the Internal Revenue Service into court battles over the divide between religion and politics.

The Alliance Defense Fund, a nonprofit legal defense group whose founders include James Dobson, the founder of Focus on the Family, sponsors the annual event, which started with 33 pastors in 2008. This year, Glenn Beck has been promoting it, calling for 1,000 religious leaders to sign on and generating additional interest at the beginning of a presidential election cycle.

“There should be no government intrusion in the pulpit,” said the Rev. James Garlow, senior pastor at Skyline Church in La Mesa, Calif., who led preachers in the battle to pass California’s Proposition 8, which banned same-sex marriage. “The freedom of speech and the freedom of religion promised under the First Amendment means pastors have full authority to say what they want to say.”

Mr. Garlow said he planned to inveigh against same-sex marriage, abortion and other touchstone issues that social conservatives oppose, and some ministers may be ready to encourage parishioners to vote only for those candidates who adhere to the same views or values.

“I tell them that as followers of Christ, you wouldn’t vote for someone who was against what God said in his word,” Mr. Garlow said. “I will,  in effect, oppose several candidates and — de facto — endorse others.”

Two Republican candidates in particular, Gov. Rick Perry of Texas and Representative Michele Bachmann of Minnesota, would presumably benefit from some pulpit politics on Sunday, since they have been courting Christian conservatives this year.

Participating ministers plan to send tapes of their sermons to the I.R.S., effectively providing the agency with evidence it could use to take them to court.

But if history is any indication, the I.R.S. may continue to steer clear of the taunts.

“It’s frustrating,” said Erik Stanley, senior legal counsel at Alliance Defense. “The law is on the books but they don’t enforce it, leaving churches in limbo.”

Supporters of the law are equally vexed by the tax agency’s perceived inaction. “We have grave concerns over the current inability of the I.R.S. to enforce the federal tax laws applicable to churches,” a group of 13 ministers in Ohio wrote in a letter to the Treasury secretary, Timothy F. Geithner, in July.

Marcus Owens, the lawyer representing the Ohio ministers, warned that the I.R.S.’s failure to pursue churches for politicking violations would encourage more donations to support their efforts, taking further advantage of the new leeway given to advocacy groups under the Supreme Court’s decision last year in the Citizens United case.

Lois G. Lerner, director of the agency’s Exempt Organizations Division, said in an e-mail that “education has been and remains the first goal of the I.R.S.’s program on political activity by tax-exempt organizations.” The agency has posted “guidance” on what churches can and cannot do on its Web site.

The agency says it has continued to do audits of some churches, but those are not disclosed. Mr. Stanley, Mr. Owens and other lawyers say they are virtually certain it has no continuing audits of church political activity, an issue that has been a source of contention in recent elections.

The alliance and many other advocates regard a 1954 law prohibiting churches and their leaders from engaging in political campaigning as a violation of the First Amendment and wish to see the issue played out in court. The organization points to the rich tradition of political activism by churches in some of the nation’s most controversial battles, including the pre-Revolutionary war opposition to taxation by the British, slavery and child labor.

The legislation, sponsored by Lyndon Baines Johnson, then a senator, muzzled all charities in regards to partisan politics, and its impact on churches may have been an unintended consequence. At the time, he was locked in a battle with two nonprofit groups that were loudly calling him a closet communist.

Thirty years later, a group of senators led by Charles E. Grassley, Republican of Iowa, passed legislation to try to rein in the agency a bit in doing some audits. While audits of churches continued over the years, they appeared to have slowed down considerably after a judge rebuffed the agency’s actions in a case involving the Living Word Christian Center and a supposed endorsement of Ms. Bachmann in 2007. The I.R.S. had eliminated positions through a reorganization, and therefore, according to the judge, had not followed the law when determining who could authorize such audits.

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