The gun background check system that President Obama and many legislators hope to expand is full of holes, says the Wall Street Journal. The National Instant Criminal Background Check System, which federally licensed dealers must use to check the credentials of potential gun buyers, doesn't include millions of people legally barred from owning guns, researchers and advocates say. Fourteen states list fewer than five people flagged for mental-health issues.

Researchers cite major gaps in filing records of known drug offenders, who are temporarily prohibited from buying firearms. States are much better at reporting the names of people convicted of felonies. "Many states are still failing to do the bare minimum," said Mark Glaze of Mayors Against Illegal Guns. "We know they have hundreds of thousands of records sitting in state agencies." Obama today will detail his policy response to the Newtown, Ct., elementary-school shooting that killed 20 children and seven adults last month. Alan Gottlieb of the Second Amendment Foundation in Bellevue, Wa., said that past efforts to expand the background-check system have included unacceptable provisions such as making organizers of gun shows criminally liable for errors. The background-check system tends to break down on weekends, when gun shows often swell traffic.