But no matter what the I.R.S. says, the amendment in the House bill would open the floodgates to politicking by charities. Charities today make enormous use of social media. A charity’s webpage often serves as its most important public gateway. Nothing in the House revision of the Johnson amendment forbids speeches, sermons, policy discussions or other activities that include electioneering from being posted on that webpage, streamed or tweeted. Communicating this way would cost the charity next to nothing and would probably qualify as a “de minimis” expense. In our digital era, the communicative impact of an exception for de minimis financial outlays is far more than de minimis.

The sponsors of the proposed change to the Johnson amendment may have intended to permit only brief, occasional instances of electioneering. We know that established charities, particularly churches, engage in such activity now. But the House proposal, if enacted as written, will do far more than bless current practice. Given that the I.R.S. is already suffering from too few enforcement resources, the I.R.S. may well hesitate to take action against possible violations of this de minimis limit. As a practical matter, a de minimis exception will come close to repealing the Johnson amendment completely.

Other tax-exempt organizations (such as section 501(c)(4) welfare organizations) can already engage in electioneering to a considerable extent. The Johnson amendment does not apply to them. But it is precisely because of the Johnson amendment’s prohibition on electioneering that charities have been a sanctuary in our increasingly partisan world. Over time, permitting charities to engage directly in electoral politics will reduce the respect they have long been afforded. In the long run, it will harm the sector. That is why so many charities, including many religious organizations, have opposed any change to the Johnson amendment.

Contributions to charities are deductible; contributions to PACs and section 501(c)(4) social welfare organizations are not. Because charities can have enormous influence on political campaigns with very little expense, many who wish to intervene in political campaigns will shift their contribution from PACs and social welfare organizations to charities. Currently, the House proposal operates for five years, from Jan. 1, 2019, to Dec. 31, 2023. The Joint Committee on Taxation estimates the revenue loss for this five-year period at $2.1 billion. This number probably underestimates the actual cost of the House’s proposed change to the Johnson amendment. Charities that make a decision to electioneer will attract large donations from donors who would like to obtain deductions and influence elections in one fell swoop.

The House proposal also encourages the establishment of new entities to take advantage of the revised rules. These newly created organizations would establish their own norms as to what is “regular and customary.” In short order, organizations would be formed precisely to take advantage of this new electioneering rule.