GOP senators press IRS to keep nonprofit donors secret

"The privacy interests of donors is widely recognized and valued. Various public policy initiatives have rightly encouraged donations to social welfare organizations, and these efforts are threatened when private information about donors is not adequately protected," the letter states.

The new letter, from Sen. Orrin HatchOrrin HatchInternet companies dominate tech lobbying Senate panel approves pension rescue for coal miners Overnight Tech: GOP says internet fight isn't over | EU chief defends Apple tax ruling | Feds roll out self-driving car guidelines | Netflix's China worries MORE (R-Utah) and other GOP senators, says that, by requesting the confidential donor names, the agency has set in motion a process that will result in the names being available for public viewing at the IRS when the investigated groups are approved to become a 501(c)(4).

"The IRS appears to be circumventing the statutory privacy protections that Congress has long provided donors," exposing the donors to "possible harassment," the Republicans said."The public release of private donor information exposes citizens to possible harassment and intimidation by those who oppose the goals of the charitable organization."

Republicans and Democrats on Capitol Hill have been clashing over 501(c)(4) and other tax-exempt groups, some of which are spending millions of dollars this year on election advertising. 

The IRS currently says that the primary purpose of 501(c)(4) groups should not be political, which has led some legal analysts to assert that those organizations should use less than 50 percent of their budget on political causes.  

Watchdogs argue groups are misusing the 501(c)(4) tax-exempt status to keep their donors secret as they spend millions on election ads. 

The Republican senators requested that the IRS provide the statutory authority to require donor names, the frequency of requests for the information, and which officials were involved in requesting and approving the "questions requesting donor names," among other issues.

Along with Hatch, the Republican senators who signed the letter were Mitch McConnellMitch McConnellShutdown risk grows over Flint Senate poised to override Obama veto Overnight Finance: Four days left to avert shutdown | Conservative group bucks spending bill | Lawmakers play catch-up on smartphone banking MORE (Ky.), Mike EnziMike EnziOvernight Energy: Obama integrates climate change into national security planning Senate panel approves pension rescue for coal miners GOP pressures Kerry on Russia's use of Iranian airbase MORE (Wyo.), Lamar AlexanderLamar AlexanderOvernight Regulation: Lawsuits pile up against Obama overtime rule The American people are restive, discouraged and sometimes suicidal GOP chairman eyes lame-duck for passing medical cures bill MORE (Tenn.), John CornynJohn CornynSenate poised to override Obama veto Senate to vote on 9/11 veto override Wednesday This week: Shutdown deadline looms over Congress MORE (Texas), Kay Bailey Hutchison (Texas), Jon Kyl (Ariz.), Bob CorkerBob CorkerSenate poised to override Obama veto US general calls out Pakistan on support for Afghan militants This week: Shutdown deadline looms over Congress MORE (Tenn.), Pat RobertsPat RobertsSenate panel approves pension rescue for coal miners Congress set for Saudi showdown with Obama GOP pressures Kerry on Russia's use of Iranian airbase MORE (Kan.), John ThuneJohn ThuneOvernight Tech: Tech pushes for debate spotlight | Disney may bid for Twitter | Dem seeks Yahoo probe Google backs Obama's internet transition plan Week ahead in tech: Key test for FCC's TV-box plan MORE (S.D.) and Rand PaulRand PaulConservative group presses GOP to vote against spending bill Saudi skeptics gain strength in Congress Senators challenge status quo on Saudi arms sales MORE (Ky.).

— Bernie Becker contributed to this report.