If ministers want to endorse political candidates then their ministries should be taxed because they have become active political organizations that are partisan in nature and by extension adjuncts to any political campaign and political party.

Laurie Goldstein, New York Times, writes:

The protest, called Pulpit Freedom Sunday, was organized by the Alliance Defense Fund, a consortium of Christian lawyers that fights for conservative religious and social causes. When the fund first announced the protest this year, it said it planned to have 50 ministers taking part. As of Thursday it said it had hundreds of volunteers, but had selected only 33 who were fully aware of the risks and benefits...

Erik Stanley, senior legal counsel with the Alliance Defense Fund, said: “This is not something these churches want to do in secrecy and hiding. In fact, they don’t believe they’re doing anything wrong. They don’t believe they’re violating the law.

“What they’re doing is talking to their congregations about biblical issues related to candidates and elections, and they believe they have the constitutional right to do that.”

The protest is challenging an amendment to the tax code passed by Congress in 1954 saying that charitable organizations known as 501(c)(3)’s, which accept tax-deductible contributions, cannot intervene in political campaigns. The legislation was intended to prevent nonprofit organizations from funneling money and resources to political candidates....

Clearly the Alliance Defense Fund's lawyers are inducing ministers to undermine tax laws.  The New York Times article continues:

Three former I.R.S. officials, now lawyers in a Washington firm, recently sent a letter to the I.R.S.’s Office of Professional Responsibility urging that the Alliance Defense Fund and its lawyers be investigated for “inducing churches to engage in conduct designed to violate federal tax law in a direct and blatant matter.”