Rules rolling back limits on donations by churches and political parties have been tucked into appropriations bills in the House and Senate. (Joshua Roberts/Reuters)

A handful of provisions tucked into a pair of must-pass bills under consideration in Congress this month could reshape the financing of political campaigns and give further cover to donors who want to keep their contributions private.

One measure would roll back limits on churches, which are prohibited under current law from advocating for candidates because of their tax-exempt status.

Other changes would relax rules affecting secret and wealthy donors and increase the amount of cash that political parties could spend on candidates.

The adjustments are being considered in the form of “riders,” or provisions that are tacked on to unrelated bills. Such attachments are controversial because they can pass without a separate vote or debate. The maneuver also masks the identity of the member of Congress who proposed each change.

In this case, lawmakers have attached them to House and Senate versions of appropriations bills, which must pass this month to keep the government operational. Ultimately, one or more may be dropped as part of budget negotiations, but the proposals have nevertheless drawn a sharp rebuke from government watchdog groups.

On Thursday, a coalition of two dozen such groups released a letter urging Congress to reject these riders.

“They hurt the public and it’s completely inappropriate to use a spending bill to do significant policy changes like these,” Lisa Gilbert, vice president of legislative affairs at Public Citizen, said in an interview.

The most significant and best-known proposal would repeal part of the Johnson Amendment, which limits political activity by tax-exempt churches and nonprofit groups.

In recent years, a growing chorus of social conservatives and Republican politicians have said the law unfairly limits the free-speech rights of religious leaders. President Trump has promised to repeal it as his top priority for protecting religious freedom.

“I think that many of the religious organizations make a good point that they should be able to endorse candidates from the pulpit,” said David Keating, president of the nonprofit Institute for Free Speech, which opposes limits on political speech and advertising.

But critics say such a change would effectively turn religious organizations that receive charitable tax donations into political action committees. It would also unleash a torrent of new players into political financing.

Another budget rider, this one attached to the Senate version of the budget bill, would relax caps on the amount of money that candidates can spend in coordination with their parties for communications. Currently, the candidates and parties can’t use the same vendor for advertising or public relations, but this change would allow them to do so, campaign finance experts said.

Senate Majority Leader Mitch McConnell (R-Ky.) supported such a change in the 2015 budget negotiations. But it met with objections, not only from congressional Democrats, but also some conservatives who said it would further entrench the power of the major political parties. Together, the two factions helped kill the provision.

This proposal may again be negotiated out of the final bill, given the conservative resistance. In 2015, McConnell said his proposal “would be a major benefit to both the political parties in a period during which more and more information flow is conducted by outside groups.”

Campaign finance watchdogs say this provision would allow mega-donors to exercise greater influence in politics.

“The reason we limit the amount that any individual donor can give to a presidential candidate is to prevent corruption or the appearance of corruption,” said Brendan Fischer, who directs the federal regulatory work of the advocacy group Campaign Legal Center. “Big donors likely will expect a level of gratitude from the candidate in a size commensurate with the size of the check.”

One provision in the House budget bill would prevent new rules requiring businesses seeking federal contracts to disclose their political spending.

It also continues two riders already written into existing law: One blocks the Securities and Exchange Commission from acting on proposed rules that would require publicly traded companies to disclose their political contributions to shareholders; another blocks the Internal Revenue Service from creating new standards for “dark money” groups, which are not required to disclose their donors or political spending.

Mike DeBonis contributed to this report.