President Obama and former President George W. Bush at the dedication of the George W. Bush library in Dallas. Alex Wong/Getty Images hide caption

itoggle caption Alex Wong/Getty Images

Former Arizona Rep. Gabrielle Giffords and her husband, Mark Kelly, at an April 16 ceremony naming a Capitol Hill conference room for her aide Gabe Zimmerman. Zimmerman died in the same Tucson, Ariz., shootings that Giffords wounded. Saul Loeb/AFP/Getty Images hide caption

itoggle caption Saul Loeb/AFP/Getty Images

Sen. Susan Collins, a Maine Republican, and fellow GOP senators accused the Obama administration of creating a "manufactured crisis" by furloughing FAA air traffic controllers and causing delayed flights. J. Scott Applewhite/AP hide caption

itoggle caption J. Scott Applewhite/AP

Sen. Chuck Schumer, D-N.Y. (right), talks during a hearing at which he angered Sen. Chuck Grassley, R-Iowa (far left). Grassley thought Schumer was accusing him of using the Boston bombings as an excuse to slow or kill the immigration overhaul. J. Scott Applewhite/AP hide caption

itoggle caption J. Scott Applewhite/AP

Sen. Joe Manchin, D-W.Va., meets in his office last week with families of victims of the Sandy Hook Elementary School shooting in Newtown, Conn. A bipartisan plan to expand background checks for gun buyers was defeated Wednesday in the Senate. J. Scott Applewhite/AP hide caption

itoggle caption J. Scott Applewhite/AP

Mark Barden, the father of a young Newtown, Conn., shooting victim, speaks at a White House news conference on Wednesday, with President Obama and former Rep. Gabby Giffords. Obama denounced the Senate's defeat of a measure to expand background checks for gun buyers. "This was a pretty shameful day in Washington," he said. Carolyn Kaster/AP hide caption

itoggle caption Carolyn Kaster/AP

President Obama leaves the White House briefing room Tuesday after making a statement about the bombings at the Boston Marathon. Mark Wilson/Getty Images hide caption

itoggle caption Mark Wilson/Getty Images

Sen. Mitch McConnell and his wife, former Labor Secretary Elaine Chao, at a Republican dinner in Winchester, Ky., last month. Roger Alford/AP hide caption

itoggle caption Roger Alford/AP

Jissela Centeno and son, Matthew Pineda, hold an American flag at a rally for immigration reform at the U.S. Capitol on Wednesday. Charles Dharapak/AP hide caption

itoggle caption Charles Dharapak/AP

People stood in line to vote on Election Day 2012 at the Wake County Firearms Education and Training Center in Apex, N.C. Gerry Broome/AP hide caption

itoggle caption Gerry Broome/AP

President Obama prepares to depart San Francisco on Thursday. Jewel Samad/AFP/Getty Images hide caption

itoggle caption Jewel Samad/AFP/Getty Images

Rep. Bill Cassidy, R-La. (right), poses with his family and House Speaker John Boehner at the start of the new Congress, on Jan. 3. On Wednesday, Cassidy announced that he would challenge Democratic Sen. Mary Landrieu in 2014. Cliff Owen/AP hide caption

itoggle caption Cliff Owen/AP