America has seen mass shootings - the frantic and often hopeless response, the makeshift memorials and the politicians promising change. That never happened, but as Vice President Joe Biden begins meetings on the issue of gun violence he says this time its different. After 20 children and six adults were killed in their Connecticut classroom, the gun control advocates who met at the White House on Wednesday believe Americans are ready for some regulation. Al Jazeera's Patty Culhane reports from Washington, DC.