Setting the stage for a collision of religion and politics, Christian ministers from 22 states plan to use their pulpits Sunday to deliver political sermons or endorse presidential candidates, defying a federal ban on campaigning by nonprofit groups.

The pastors' advocacy would be a deliberate attempt to challenge IRS rules against political speech.

That would allow their patron, the conservative legal group Alliance Defense Fund, to challenge the IRS rules, a risky strategy that one defense fund attorney acknowledged could cost the churches their tax-exempt status. Congress made it illegal in 1954 for tax-exempt groups to support or oppose political candidates publicly.

"I'm going to talk about the un-biblical stands that Barack Obama takes. Nobody who follows the Bible can vote for him," said the Rev. Wiley S. Drake of First Southern Baptist Church of Buena Park, Calif. "We may not be politically correct, but we are going to be biblically correct. We are going to vote for those who follow the Bible."

Drake was the target of a recent IRS investigation into his endorsement last year of former Arkansas governor and Republican presidential candidate Mike Huckabee. In the end, Drake was cleared.

Drake and 32 other pastors who have signed on to the "pulpit initiative" have sparked loud condemnations by fellow clergy and advocates of the separation of church and state. (It was not clear yesterday whether any Massachusetts pastors would take part; the Alliance Defense Fund's website said participants will be named afterward.)

These critics, such as Americans United for Separation of Church and State, argue that Sunday's sermons at churches in Oregon, Texas, New Mexico, Pennsylvania, and other states would violate federal tax law by politicizing the pulpit. That, they believe, will undercut the independence churches have long enjoyed to speak out about moral and ethical issues in American life, including women's suffrage, child labor and civil rights.

"The integrity of the religious community is at stake when religion and politics become entangled," said the Rev. Eric Williams of the North Congregational United Church of Christ in Columbus, Ohio.

Williams was recruited for the defense fund but instead joined with 54 other Christian and Jewish clergy members to file a complaint against the initiative with the IRS.

The religious leaders asked the agency to stop the Arizona-based defense fund from recruiting churches and to investigate whether its efforts may jeopardize its own tax-exempt status.

A separate group of 180 ministers, rabbis, and imams also has sought to counter the initiative. Members of the Interfaith Alliance - which includes the nation's top Episcopal bishop - have signed a pledge to refrain from electioneering in their houses of worship.

"Political activity and political expressions are very important, but partisan politics are . . . a death knell to the prophetic freedom that any religious organization must protect," said the Rev. Ed Bacon, rector of All Saints Episcopal Church in Pasadena, Calif., who signed the pledge.

© Copyright 2008 Globe Newspaper Company.