Washington (RNS)—A Washington-based watchdog group has filed six complaints with the Internal Revenue Service after dozens of pastors participated in a challenge to rules that ban politicking from the pulpit.

At least 31 pastors took part in “Pulpit Freedom Sunday” Sept. 28, according to the initiative’s organizers at the Alliance Defense Fund, a conservative Christian law firm based in Arizona.

“These pastors flagrantly violated the law and now must deal with the consequences,” said Barry Lynn, executive director of Americans United for Separation of Church and State in a recent statement.

Pastors endorsed Sen. John McCain for president in five of the six churches, Lynn noted.

Gary McCaleb, senior counsel with ADF, said, “It’s not a matter of separation of church and state when you’ve got the IRS in the pew. That’s oppression of free speech.”

He said 31 pastors who agreed to participate in the plan preached on the Sunday. The ADF has asked the pastors, most of whom are evangelical, to send their sermons to the law firm, which plans a court challenge of the IRS rules against partisan politicking by tax-exempt organizations.

Asked if all the participating pastors had endorsed a candidate for president, McCaleb answered, “I think some had a pretty direct statement.” He said the goal was to find a group of pastors who supported an “exercise of faith” that could lead to a Supreme Court case.

Americans United’s complaints were filed against Calvary Chapel on the King’s Highway in Philadelphia; Bethlehem First Baptist Church of Bethlehem, Ga.; Fairview Baptist Church in Edmond, Okla.; Warroad Community Church in Warroad, Minn; New Life Church in West Bend, Wis., and First Southern Baptist Church of Buena Park, Calif.