FILE - In this Friday, March 22, 2013, file photo, the exterior of the Internal Revenue Service building in Washington, is shown. The Obama administration, on Tuesday, Nov. 26, 2013, launched a bid to rein in the use of tax-exempt groups for political campaigning. The effort is an attempt to reduce the role of loosely regulated big-money political outfits like GOP political guru Karl Rove's Crossroads GPS and the pro-Obama Priorities USA. The Internal Revenue Service and the Treasury Department said they want to prohibit such groups from using "candidate-related political activity" like running ads, registering voters or distributing campaign literature as activities that qualify them to be tax-exempt "social welfare" organizations. (AP Photo/Susan Walsh, File)

Photo by: Susan Walsh

FILE - In this Friday, March 22, 2013, file photo, the exterior of the Internal Revenue Service building in Washington, is shown. The Obama administration, on Tuesday, Nov. 26, 2013, launched a bid to rein in the use of tax-exempt groups for political campaigning. The effort is an attempt to reduce the role of loosely regulated big-money political outfits like GOP political guru Karl Rove's Crossroads GPS and the pro-Obama Priorities USA. The Internal Revenue Service and the Treasury Department said they want to prohibit such groups from using "candidate-related political activity" like running ads, registering voters or distributing campaign literature as activities that qualify them to be tax-exempt "social welfare" organizations. (AP Photo/Susan Walsh, File)