WASHINGTON — Declaring that religious freedom is “under threat,” President Donald Trump vowed Thursday to repeal a rarely enforced IRS rule that says pastors who endorse candidates from the pulpit risk losing their tax-exempt status.

“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 during remarks at the National Prayer Breakfast, a high-profile event bringing together faith leaders, politicians and dignitaries.

Trump also defended his recent executive order on immigration, decrying “generous” immigration policies and arguing that there are people who seek to enter the country “for the purpose of spreading violence or oppressing other people based upon their faith.” He also pledged to take more immigration action in the name of religious liberty.

“In the coming days we will develop a system to help ensure that those admitted into our country fully embrace our values of religious and personal liberty and that they reject any form of oppression and discrimination,” Trump said.

He did not detail how he might scrap the IRS rule, which he has previously pledged to do away with. The rule, named after then-Sen. Lyndon Johnson, has been in place since 1954, but it is very rare for a church to actually be penalized. And while some conservative Christians would like to see it abolished, others, especially the younger generation, support a clear separation of church and politics.

Repeal does not appear to have widespread public support. Eight in 10 Americans said it was inappropriate for pastors to endorse a candidate in church in a poll released last September by Lifeway Research, a religious survey firm based in Nashville.

For many religious conservatives, whose overwhelming support helped propel Trump to the White House, a more pressing issue they hope he will address is protection for faith-based charities, schools and ministries who object to same-sex marriage and abortion.

The president made no mention at the prayer breakfast of other steps he may take, saying only that religious freedom is a “sacred right.”