Ismaaiyl Brinsley, the man who killed two New York City police officers on Saturday, was a felon barred under federal law from buying a gun. “In fact, it’s weak gun laws that enable felons, domestic abusers, and the mentally ill to arm themselves,” writes The New Republic‘s Rebecca Leber. “Whereas licensed gun sellers must conduct background checks, unlicensed secondary market sellers face no such requirement in more laissez-faire states.”

New York Police Department Commissioner Bill Bratton and his predecessor Raymond Kelly have both supported tougher regulations. In a New York Daily News op-ed, Kelly cited data concerning the large number of out-of-state guns used in New York City crimes. Although New York and Maryland require background checks on all gun sales, the black market in both states is “fueled by weaker gun laws on secondary market sales in other states,” says Arkadi Gerney, a gun violence expert at the Center for American Progress.

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