Gun Control, Back on the Front Burner

With Republicans in the majority, gun control has almost no chance on Capitol Hill. But last week's mass killing in Oregon has changed the political calculus. Today, Senate Democrats promised to block other action until GOP members are forced to vote against background checks and other provisions. Next week, Hillary Clinton, Martin O'Malley and Bernie Sanders will display their differences in the party's first presidential debate. We look at the prospects for maintaining momentum for gun control until the November election.