On previous occasions, we have mentioned the fact that specific screw-ups by federal officials have placed guns in the hands of some of America’s most notorious mass shooters.

If not for sloppy record-keeping and boneheaded mistakes by individual officials, the shooters in incidents in Charleston, S.C., at Virginia Tech, and in Sunderland Springs, Texas, would not have been permitted to purchase guns. There could be many, many similar cases where guns were used in crimes other than mass shootings.