"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 Grant HatchMellman: What happened after Ginsburg? Bottom line Bottom line 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."

ADVERTISEMENT

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 McConnellAddison (Mitch) Mitchell McConnellBiden leans on Obama-era appointees on climate Kentucky Republican committee rejects resolution urging McConnell to condemn Trump impeachment Calls grow for 9/11-style panel to probe Capitol attack MORE (Ky.), Mike EnziMichael (Mike) Bradley EnziSenate swears-in six new lawmakers as 117th Congress convenes With Senate at stake, Georgia is on all our minds Wyoming mask mandate backed by GOP lawmakers goes into effect MORE (Wyo.), Lamar AlexanderLamar AlexanderCongress addressed surprise medical bills, but the issue is not resolved Trump renominates Judy Shelton in last-ditch bid to reshape Fed Senate swears-in six new lawmakers as 117th Congress convenes MORE (Tenn.), John CornynJohn CornynTrump impeachment trial to begin week of Feb. 8 Limbaugh falsely says Biden didn't win legitimately while reacting to inauguration Top Texas Democratic Party staffers to step down after underwhelming election results MORE (Texas), Kay Bailey Hutchison (Texas), Jon Kyl (Ariz.), Bob CorkerRobert (Bob) Phillips CorkerGOP lawmaker patience runs thin with Trump tactics Former GOP senator: Republicans cannot let Trump's 'reckless' post-election claims stand Cornyn: Relationships with Trump like 'women who get married and think they're going to change their spouse' MORE (Tenn.), Pat RobertsCharles (Pat) Patrick RobertsSenate swears-in six new lawmakers as 117th Congress convenes Window quickly closing for big coronavirus deal Trump's controversial Fed nominee stalled after Senate setback MORE (Kan.), John ThuneJohn Randolph ThuneThe Hill's Morning Report - Biden's crisis agenda hits headwinds Senate chaos threatens to slow Biden's agenda NRSC chair says he'll back GOP incumbents against Trump primary challengers MORE (S.D.) and Rand PaulRandal (Rand) Howard PaulSunday shows preview: All eyes on Biden administration to tackle coronavirus The Hill's Morning Report - Biden takes office, calls for end to 'uncivil war' Senate confirms Biden's intel chief, giving him first Cabinet official MORE (Ky.).

— Bernie Becker contributed to this report.