The head of the Internal Revenue Service this week signaled that his agency will re-write proposed new limits on the political activities of nonprofit advocacy groups, quelling concerns from the left about overreach but failing to win over conservatives.

Lawmakers and policy analysts on both sides of the political spectrum have voiced opposition to the draft guidelines, which would prohibit tax-exempt organizations from engaging in certain election-related activities including voter-registration and get-out-the-vote drives.

Conservatives have argued that the proposals are part of an Obama administration plot to silence criticism from the right. Liberals have said the plans simply go too far and need reworking.

IRS Commissioner John Koskinen said in an interview with USA Today on Monday that his agency is likely to “re-propose a redefined rule and ask for more public comment,” adding that the process is likely to last through at least the end of the year.

Public Citizen, an advocacy group founded by former Green Party activist and presidential candidate Ralph Nader, described Koskinen’s remarks as “a real victory for the public and groups most affected by the proposed rule.”

The group has called for “clear, fair rules that would apply to all nonprofits and would encourage nonpartisan civic engagement while removing opportunities for abuse.”

Similarly, the American Civil Liberties Union, which has criticized the draft guidelines, said the new rules should “draw a true bright line to ensure that issue advocacy and non-partisan voter work, on both the left and right, aren’t treated like partisan electioneering.”

The existing guidelines, which affect tax-exempt 501(c)(4) organizations, say the groups must be “primarily engaged” in social welfare work as opposed to political efforts. Critics say the rules lack clarity about what constitutes prohibited activity.

Senate Minority Leader Mitch McConnell (R-Ky.), one of the staunchest opponents of the limits, responded with backhanded approval to the IRS walking back its initial proposals. He has said that the Obama administration should drop its plans for new regulations affecting nonprofit advocacy groups.

“The commissioner has the ability to stop the IRS from stepping on the First Amendment altogether, and that’s exactly what he should do,” McConnell said in a statement on Tuesday.

Cleta Mitchell, a conservative election-law expert, said in an interview on Tuesday that the Obama administration has been working “behind closed doors” and “in secret” to develop new rules that would hinder nonprofit advocacy groups with right-leaning policy positions.

“It doesn’t give me comfort that [Koskinen] says he’s re-writing the draft regulations,” Mitchell said. “This is a flawed process that is going to continue to produce a flawed product.”

Koskinen’s remarks came less than a week after the House Ways and Means Committee voted along party lines to request criminal charges against former IRS official Lois Lerner, whom Republicans have accused of targeting conservative groups and plotting to develop new tax-exemption regulations without public notice, among other allegations.

Lerner’s attorney, William Taylor, has said repeatedly that his client did nothing wrong. He claims Republicans are attacking his client to score political points before the upcoming midterm elections.

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