In his address to the National Prayer Breakfast on Thursday, President Trump vowed to "get rid of and totally destroy the Johnson Amendment and allow our representatives of faith to speak freely and without fear of retribution."
Some conservative Christian groups will welcome the promise, but many Americans may wonder what Trump was talking about. Here are five basic questions that we can answer.
1. What is the Johnson Amendment?
The Johnson Amendment regulates what tax-exempt organizations such as churches can do in the political arena.
Under terms of the 1954 legislation (named for its principal sponsor, then-Sen. Lyndon Johnson), churches and other non-profit organizations that are exempt from taxation "are absolutely prohibited from directly or indirectly participating in, or intervening in, any political campaign on behalf of (or in opposition to) any candidate for elective public office," according to the IRS website.
Organizations claiming tax-exempt status cannot collect contributions on behalf of political campaigns or make any statement for or against a particular candidate. Clergy are not allowed to endorse candidates from the pulpit. (Despite Trump's promise to "totally destroy" the amendment, the president does not have the authority to do so on his own. Only Congress can repeal a law, in this case an amendment to the tax code.)
2. Does this prohibit all types of political activity in churches?
The law is fairly narrow in scope. Nonpartisan voter education activities and church-organized voter registration drives are legal. Pastors are free to preach on social and political issues of concern. Churches can publish "issue guides" for voters.
3. Who wants the Johnson Amendment repealed?
Though white evangelical Protestants have been active in pushing for the amendment's repeal, other religious groups have been more likely to test its limits.
A 2016 study by the Pew Research Center found that black Protestants have been more likely than other Christian groups to report having heard their clergy speak out clearly on the merits or faults of a particular candidate. The study found that 28 percent of black Protestants heard their clergy speak in support of Hillary Clinton during the 2016 campaign, while about one-in-five black Protestants said they had heard their ministers denounce Donald Trump.
By comparison, just 4 percent of white evangelicals reported having heard their clergy speak in favor of a presidential candidate (2 percent each for Trump and Clinton), while 7 percent heard their clergy speak against a candidate (mostly Clinton).
4. Is this just about free speech for churches and pastors?
No. It's also about money and politics.
Conservative groups which favor a greater role for religion in the public space, such as the Alliance Defending Freedom, have long sought to repeal the amendment, arguing that it restricts free speech by censoring the content of a pastor's sermon.
Overturning the law, however, would also have major implications for campaign finance. If churches or clergy are allowed to participate in political campaigns, tax-free donations to the churches could go to support a political candidate. Religious organizations could become bigger money players in politics.
5. Have any churches landed in trouble for violating the Johnson Amendment?
Despite the controversy surrounding the Johnson Amendment, the Internal Revenue Service has not been especially active in enforcing it. Since 2008, the Alliance Defending Freedom has organized "Pulpit Freedom Sunday," encouraging pastors to give explicitly political sermons in defiance of the law.
The IRS, however, has rarely moved to take away a church's tax exemption. According to the Alliance, as reported by the Washington Post, only one of more than 2000 Christian clergy deliberately challenging the law since 2008 has been audited, and none has been punished.