Universal Background Checks: Shouldn't We Review the Statistics?

Regarding the recent high-profile tragedies at Newtown, Aurora, Tucson, and at the Clackamas mall in Oregon: Newtown and Clackamas mall involved stolen guns from lawful owners, so a background check is irrelevant. The killers at Aurora and Tucson were both severely mentally ill -- but because we decided to destroy our state mental health system in the 1970s, neither had been involuntarily committed, and so both passed the existing national background check system at dealers.

It is not enough to feel that this will make a difference; we need to make evidence-based decisions about what laws to pass. Those who refuse to do math are doomed to talk nonsense.