The debate over gun control

A worker sets up a sign for a news conference held by Mayors Against Illegal Guns on Capitol Hill.  (Alex Wong / Getty Images)

Gun violence victims and gun control advocates gather at Cornell Square Park in Chicago to mark the anniversary of the Sandy Hook Elementary School shooting.  (Scott Olson / Getty Images)

Alan Gottlieb, chairman of the Citizens Committee for the Right to Keep and Bear Arms, prepares to read a statement as he stands with the first batch of signatures for a gun rights initiative delivered to the Secretary of State’s office, in Olympia, Wash.   (Elaine Thompson / Associated Press)

Cody Wilson holding what he calls a Liberator pistol, completely made on a 3-D printer at his home in Austin. Congress has voted to extend a ban on plastic firearms that can slip past airport and school metal detectors and X-ray machines.  (Jay Janner / Associated Press)

Anti-gun violence demonstrators hold signs condemning the National Rifle Assn. during a protest in McPhearson Square in Washington, D.C.  (Chip Somodevilla / Getty Images)

President Obama and Vice President Biden listen to remarks from Mark Barden, whose child was murdered at Sandy Hook Elementary School, alongside other victims of gun violence, following a Senate vote on background checks for firearm sales.  (Michael Reynolds / EPA)

Mark Barden, left, who lost his son Daniel in Newtown, Conn., speaks to introduce President Obama during a news conference following the defeat in the Senate of a bill to expand background checks on guns.  (Jacquelyn Martin / Associated Press)

Sen. Dianne Feinstein, (D-Calif.) in an elevator on Capitol Hill in Washington after speaking on the Senate floor about gun legislation.  (Charles Dharapak / Associated Press)

Family members of Newtown shooting victims step off Air Force One with President Obama upon arrival at Andrews Air Force Base in Maryland.  (Mandel Ngan / AFP/Getty Images)

Vice President Joe Biden speaks about gun legislation in the Eisenhower Executive Office Building at the White House.  (Charles Dharapak / Associated Press)

Senate Judiciary Committee member Sen. Lindsey Graham (R-S.C.) talks about gun legislation during the committee’s hearing on Capitol Hill.  (Susan Walsh / Associated Press)

Anti-gun control protesters outside the Denver Police Academy, where President Obama was speaking on gun control.  (Aaron Ontiveroz / Associated Press)

Faces of Sandy Hook Elementary School victims are seen behind Sen. Dianne Feinstein (D-Calif.) as she speaks about an assault weapons ban before the Senate Judiciary Committee on Capitol Hill.  (Susan Walsh / Associated Press)

House Speaker John Boehner of Ohio takes questions from reporters on gun control, immigration and the budget during a news conference on Capitol Hill.  (J. Scott Applewhite / Associated Press)

A young protester attends a rally and march to support federal and state gun control proposals in Harlem, New York City.  (Timothy A. Clary / AFP/Getty Images)

Sen. Chuck Schumer (D-N.Y.) delivers remarks during a news conference with lawmakers, family members and victims of gun violence, on Capitol Hill.  (Michael Reynolds / EPA)

Audience members applaud as President Obama speaks on gun control on at the University of Hartford.  (Mandel Ngan / AFP/Getty Images)

Craig Bentley, wearing a pro-gun T-shirt, speaks with reporters before a speech by President Obama on gun control at the University of Hartford.  (Spencer Platt / Getty Images)

Mark Malkowski, president of Stag Arms, poses as workers move a pallet of rifles for shipment at the Stag Arms company in New Britain, Conn. Stag Arms, which employs about 230 workers, says its customers are urging it to “pick up and leave” the state.  (Charles Krupa / Associated Press)