Gun violence is a national security issue

Editor's note: Peter Bergen is a CNN national security analyst and author of "Manhunt: The Ten-Year Search for bin Laden, from 9/11 to Abbottabad" and "The Longest War: America's Enduring Conflict with al-Qaeda."
(CNN) -- The proliferation of semiautomatic weapons in the hands of Americans of the types that were used in the Newtown massacre is sometimes framed as a public health issue in the United States.
There is considerable merit to the notion of treating gun violence as a public health matter. After all, homicides -- around...