Recent mass shooting tragedies have renewed the national debate over the 2nd Amendment. Gun ownership and homicide rates are higher in the U.S. than in any other developed nation, but gun violence has decreased over the last two decades even as gun ownership may be increasing. Over 200 years have passed since James Madison introduced the Bill of Rights, the country has changed, and so have its guns. Is the right to bear arms now at odds with the common good, or is it as necessary today as it was in 1789? The debaters are Alan Dershowitz, David Kopel, Sanford Levinson, and Eugene Volokh.