Few differences are as clarifying as attitudes towards "gun control". (The quotation marks give me away.) (1) Control advocates trust the authorities to protect us -- and to somehow enforce gun control (consider long-standing attempts at heroin control and consider how carefully the DMV screens auto drivers); and (2) Gun control advocates cannot distinguish between the gun and the owner. Mere access makes us all equally dangerous. I have problems with both thought patterns.
Tyler Cowen at Marginal Revolution cites various sources on inevitable cultural differences that contribute to U.S. violence. And American culture is different -- for better and for worse.
The many commentators to his post note that the shooter was from abroad. And international data comparisons are very difficult.