Those challenges were evident in 2007, when a gunman at Virginia Tech shot and killed 32, and Democratic Gov. Tim Kaine called for closing a loophole in the law allowing for private sales at gun shows without the same background check that licensed dealers are required to obtain.

WSJ: Few states find narrow route to gun control laws

State officials worked together to enact tougher background checks that help keep guns out of the hands of dangerous people without infringing on the rights of responsible gun owners.

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In the brief Cruz submitted to the Supreme Court, he argues that the Court could strike down the Washington DC gun ban without impacting on (declaring unconstitutional) the many state regulations prohibiting or limiting ownership of certain weapons.

FORBES: Meet Ted Cruz-Second Amendment Hypocrite