** FILE ** President Obama arrives to participate in a news conference in the Rose Garden of the White House on April 17, 2013, about measures to reduce gun violence. With Obama is former Rep. Gabby Giffords (left) and Mark Barden, the father of Newtown shooting victim Daniel. (Associated Press)

Photo by: Carolyn Kaster

** FILE ** President Obama arrives to participate in a news conference in the Rose Garden of the White House on April 17, 2013, about measures to reduce gun violence. With Obama is former Rep. Gabby Giffords (left) and Mark Barden, the father of Newtown shooting victim Daniel. (Associated Press)