Is America making progress to stem gun violence?

Aired: 12/16/2013 | 0:13:32 | Clip
One year after the Sandy Hook tragedy, violent acts like the latest shooting at a Colorado high school remind the nation that the gun debate is not over. Gwen Ifill looks at efforts to curb violence in the U.S. with Dr. Jeffrey Lieberman of the American Psychiatric Association and Paul Barrett of Bloomberg Businessweek.