House Oversight Committee Chairman Rep. Darrell Issa, R-Calif., left, confers with Rep. Jason Chaffetz, R-Utah, right, at a House Oversight Committee hearing about last year's deadly assault on the U.S. diplomatic mission in Benghazi, Libya, on Capitol Hill in Washington, Wednesday, May 8, 2013. (AP Photo/J. Scott Applewhite)
House Oversight Committee Chairman Rep. Darrell Issa, R-Calif., listens to criticism from a Democratic member of the panel during a hearing on the problems with implementation of the Obamacare healthcare program, and specifically, the HealthCare.gov website, on Capitol Hill in Washington, Wednesday, Nov. 13, 2013. (AP Photo/J. Scott Applewhite)
Rep. Darrell E. Issa, California Republican and House Oversight Committee chairman, holds up a document as he speaks to IRS official Lois Lerner on Capitol Hill in Washington on Wednesday, May 22, 2013, during the committee's hearing to investigate the extra scrutiny IRS gave to tea party and other conservative groups that applied for tax-exempt status. Ms. Lerner told the committee she did nothing wrong and then invoked her constitutional right to not answer lawmakers' questions. (Associated Press)
IRS official Lois Lerner leaves a House Oversight Committee hearing on Capitol Hill in Washington on Wednesday, May 22, 2013. Ms. Lerner told the committee she did nothing wrong and then invoked her constitutional right to not answer lawmakers' questions. At left is former IRS Commissioner Douglas Shulman; at right is Deputy Secretary of the Treasury Neal S. Wolin. (AP Photo/Carolyn Kaster)
**FILE** Internal Revenue Service Commissioner Douglas Shulman testifies on Capitol Hill in Washington before the House Oversight Committee on Aug. 2, 2012. (Associated Press)