The Johnson Amendment says that pastors who endorse candidates from the pulpit should lose their tax exempt status.
However back in May, Donald Trump signed an executive order intended to weaken the Johnson Amendment. It told the IRS to look the other way when pastors endorse candidates in violation of non-profit rules, though the IRS was already barely taking any action. Which politically can cut two ways.
At the present time, a budget bill being considered by the U.S. House Committee on Appropriations includes an amendment forbidding the IRS from devoting a single penny to investigating claims of those violations.
Source: Read more at http://www.patheos.com/blogs/friendlyatheist/2017/08/17/thousands-of-religious-leaders-want-congress-to-protect-the-johnson-amendment/#mKsBVcEaqVRaLMlJ.99
