Four gun control measures are on their way to the full Senate in April. They were approved along party lines by the Senate Judiciary Committee in the past two weeks. One bill includes an assault weapons ban and a limit on ammunition magazines. Other proposals would expand background checks and enact tougher laws against firearms trafficking and straw purchases. At the same time, addendums to spending bills could undermine both existing and proposed gun control efforts. Three months after the shooting deaths of 20 first graders in Newtown, Conn., a panel joins Diane to discuss the gun debate in Congress.