LOUISVILLE, Ky. - Kentucky Gov. Matt Bevin urged a group of preachers to embrace political speech at the pulpit despite a federal law that prohibits tax-exempt churches from endorsing political candidates.

Bevin called the federal law a “paper tiger” during an address to a group of preachers at the governor’s mansion last month.

“There is no reason to fear it; there is no reason to be silent,” the governor told the group. “And that we have been exhorted and encouraged to have this boldness and this spirit, to be unapologetic, and I would encourage you to do it.”

Get Breaking News Delivered to Your Inbox

Bevin has proven a staunchly conservative leader of Kentucky since getting elected last year by, among other things, dismantling a well-regarded health care exchange, moving to protect clerk Kim Davis in her infamous refusal to marry same-sex couples, and changing state policy in an attempt to refuse accepting refugees.

What Bevin said to the preachers veered into a controversial slice of the American tax code.

The 1954 law says tax-exempt organizations, including churches, may not participate or intervene in any “political campaign on behalf of any candidate for public office.” It is known as the Johnson Amendment, for then-Sen. Lyndon B. Johnson who pushed for it to be enacted.

Churches are allowed to advocate for a cause, just not specific candidates or political parties.

An organization called Kentuckians Against Matt Bevin posted video captured by someone at the invitation-only gathering, which was not publicized. Bevin’s comments were first reported by Louisville’s WFPL-FM.

When asked about the statements Tuesday, Bevin spokeswoman Amanda Stamper said the governor “simply encouraged the ministers to preach boldly.” She did not comment further on the gathering.

In his speech, Bevin declared that no church has ever had its tax-exempt status revoked for breaking the law.

Lisa A. Runquist, a California attorney who specializes in nonprofit and religious tax law, said it is a law with a lot of gray area that’s very difficult for the Internal Revenue Service to enforce. But she pointed to a case in the 1990s, when the IRS revoked the tax-exempt status of a New York church for buying full-page newspaper advertisements that called on Christians not to vote for Bill Clinton.

The organization Americans United for the Separation of Church and State lodged a complaint with the IRS. The IRS investigated and revoked its exempt status and a federal court upheld that decision.

But churches’ political activity is rarely so clear and so public, and Runquist said the government pursues few cases. Still, she counsels her clients to stay within the lines of the law.

“There’s always a chance that they will,” she said she tells clients. “And do you want to be the test case that goes forward?”

Americans United for the Separation of Church and State continues to file complaints with the Internal Revenue Service, said Barry Lynn, the organization’s executive director.

They’ve seen some clear violations, Lynn said. A Texas church, for example, posted a sign during the 2012 presidential election that read: “Vote for the Mormon, not the Muslim!”

But in 2009, the IRS suspended auditing churches on a regulatory technicality, according to an audit by the United States Government Accountability Office. The regulation has still not been rewritten.

“The majority of Americans - including the devout - oppose making houses of worship centers of partisan politics,” Lynn’s organization has written in its efforts to have the law enforced. “Pulpit politicking threatens to divide faith communities and erode the important boundary between church and state that make each distinct. It’s a bad deal all around.”

But the law remains unpopular with many politicians. Congressmen Steve Scalise and Jody Hice filed a bill last month that would rewrite the law to allow charities and churches to engage in any political activity that doesn’t cost money. The law has even drawn the ire of presidential candidate Donald Trump, who has pledged to repeal the amendment if elected president in November.