President Trump promised faith leaders Thursday that he would "totally destroy" the law that prohibits churches from engaging in political activity, a move that would upend 63 years of settled tax law.

In an appearance at the annual National Prayer Breakfast, Trump said he would make good on his promise to overturn the so-called Johnson Amendment, which bans public charities — including churches — from campaigning for or against a candidate for for elected office. Those who do risk losing their tax exemption.

"Among those freedoms is the right to worship according to our own beliefs. That is why I will get rid of and totally destroy the Johnson Amendment and allow our representatives of faith to speak freely and without fear of retribution," Trump said. "I will do that, remember."

The statement was met by enthusiastic applause from the religious leaders.

The 1954 law is named for its author, then-senator Lyndon Johnson. Because it's in the tax code, any change would have to come from Congress.

The position is not a new one for Trump, who used it as a selling point to evangelical voters during his campaign. In a speech to the Values Voters Summit in Washington last September, Trump said, "The first thing we have to do is give our churches their voice back. It's been taken away."

Trump argued that the Johnson amendment has restricted not just political speech, but religious speech as well. "If they want to talk about Christianity, if they want to preach, if they want to talk about politics, they're unable to do so," he said in September. "All religious leaders should be able to freely express their thoughts and feelings on religious matters."