Sadly none of this will generate the same political frisson as Mr. Obama’s call for Congress to reinstate the federal "assault weapons" ban that expired in 2004 and also prohibit high-capacity gun magazines that can hold more than 10 rounds. These are political gestures—but anyhow, over to you, Mary Landrieu, Max Baucus, Mark Begich, Mark Pryor, Mark Warner, Kay Hagan and Tim Johnson, the red-state Democratic Senators up for re-election in 2014.
The conceptual problem begins with the elastic definition of assault weapons. Mr. Obama certainly didn’t define it. The ban that was imposed in 1994 mostly regulated cosmetic features like folding stocks, pistol grips and flash suppressors and produced no measurable shift in gun crime, according to federal researchers.
Semi-automatic rifles have been on the U.S. commercial market since 1903 (from Winchester and Remington) and are in broad use among law-abiding citizens for self-defense, target shooting and sport. They accounted for about 40% of rifle sales in 2010. The AR-15, one of the guns Adam Lanza used in Newtown, is the most popular model in America—5.5% of all U.S. guns manufactured in 2007—and there are about two million in circulation.