Research Suggests Gun Background Checks Work, But They're Not Everything

Here's one topic Americans can bank on hearing about in next week's State of the Union address: gun control. The reaction to President Obama's announced gun-control measures this week was swift and entirely as expected. Gun-control advocates and many Democrats applauded his efforts; gun-rights groups and many Republicans loudly denounced the orders as executive overreach.

Expanded background checks are central to the president's proposals. His order doesn't rewrite existing laws, but it would broaden the scope of who is in the gun-selling business. It would require more gun sellers online...