THE LOGIC OF BACKGROUND CHECKS: Would a Broader Screening Requirement for Gun Buyers Reduce Violent Crime?

Three sources accounted for almost nine out of 10 crime guns: friends or family (40 percent), the street (38 percent) and theft (10 percent). It is hard to see how any national background check requirement, even one applying to all private transfers, can reasonably be expected to have a significant impact on these sources.

Thus the answer: probably not.

ADDED: Congress agrees.