President Barack Obama walks past a line of police officers as he arrives at the National Peace Officers Memorial Service on Capitol Hill, in Washington, May 15, 2013. (Drew Angerer for The New York Times)

President Barack Obama and Attorney General Eric Holder attend the National Peace Officers Memorial Service on Capitol Hill, in Washington, May 15, 2013. The Obama administration was under fire this week for controversies over the Interntal Revenue Service's targeting of conservative groups and the Justice Department's gathering of phone records from the Associated Press. (Drew Angerer for The New York Times)

From left: President Barack Obama, Attorney General Eric Holder, Homeland Security Secretary Janet Napolitano, and FBI Director Robert Mueller attend the National Peace Officers Memorial Service on Capitol Hill, in Washington, May 15, 2013. The Obama administration was under fire this week for controversies over the Interntal Revenue Service's targeting of conservative groups and the Justice Department's gathering of phone records from the Associated Press. (Drew Angerer for The New York Times)

At left, Associated Press reporter Julie Pace listens to Press Secretary Jay Carney during the White House Daily Briefing, in Washington, May 15, 2013. The Obama administration was under fire this week for controversies over the Interntal Revenue Service's targeting of conservative groups and the Justice Department's gathering of phone records from the Associated Press. (Drew Angerer for The New York Times)

President Barack Obama makes his way to the lectern to speak on the situation regarding the Internal Revenue Service in the East Room of the White House, in Washington, May 15, 2013. Obama said Wednesday the acting commissioner of the IRS had been fired, and pledged that he would work "hand-in-hand with Congress" in inquiries on the treatment of conservative groups.  (Drew Angerer for The New York Times)