A Texas church that posted a marquee message urging people to “vote for the Mormon, not the Muslim” violated federal tax law and should suffer the consequences, Americans United for Separation of Church and State told the Internal Revenue Service today.

Ray Miller, pastor of the Church in the Valley in Leakey, Texas, posted the message on the church’s marquee. The full message read, “VOTE FOR THE MORMON, NOT THE MUSLIM! THE CAPITALIST, NOT THE COMMUNIST!”

Pictures of the sign have appeared on several news website and other sources. Miller told a Texas television station that he displayed the sign because “he feels strongly about the election.”

“This sign is a blatant attempt to intervene in a political campaign,” said the Rev. Barry W. Lynn, executive director of Americans United. “I urge the IRS to crack down on this over-the-top law-breaking.”

ABC News reported that the sign “was an obvious reference to President Barack Obama, who conservatives say is a secret Muslim even though he says he is a Christian and attends church with his family.” The “Mormon” reference is to Gov. Mitt Romney, a member of the Church of Jesus Christ of Latter-day Saints.

In a letter delivered to the IRS today, Lynn requested an investigation of the matter.

“Miller may indeed have strong feelings about the election, but that does not give him the right to use his tax-exempt church to endorse a candidate,” Lynn wrote to IRS officials. “In fact, Miller’s actions are a clear and flagrant violation of the law.”

Added Lynn, “Millions of Americans are aware that this church has openly violated the law, and many of them are asking what the IRS intends to do about it. Failure to act will only spur more houses of worship to ignore the law.”

Federal law prohibits 501(c)(3) tax-exempt organizations, which includes houses of worship, from intervening in elections.