Hundreds of preachers across America were politically disobedient Sunday, following in the footsteps of Mahatma Gandhi and Dr. Martin Luther King Jr. as they publicly defied a 1954 law that gags them from preaching about politics.

The law was authored by then-Senator Lyndon B. Johnson, angry that he had been denounced from the pulpit of two churches.

Sunday is referred to as “Pulpit Freedom Sunday.” Here Jim Garlow, pastor of Skyline Church in California explains what it’s all about.

How many pastors participated? The Alliance Defense Fund, a nonprofit legal defense group, sponsors the annual event, which started with 33 pastors in 2008. This year spokespersons have called on 1,000 religious leaders to sign on.

Many of the pastors participating say that they only rarely speak out on political issues. However, they are uncomfortable with the IRS regulation — which they say violates First Amendments rights to free speech and freedom of religion. The regulation basically says that if churches are going to be exempt as non-profits, they give up the right to participate in the political process. It was wrong to make the rule in 1954, it is only enforced selectively often because someone with a grudge lodges a complaint with IRS — and it needs to come off of the books.

“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.”

Garlow told the New York Times 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.

“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.”