The Second Amendment to the U.S. Constitution states: “A well regulated Militia, being necessary to the security of a free State, the right of the people to keep and bear Arms, shall not be infringed.” Until recently, no federal appellate court had ever struck down any gun law as a violation of the Second Amendment. In fact, even laws outlawing most handgun possession, or restricting other types of firearms, had been upheld, in part, because the laws did not interfere with the functioning of state militias.
Then, in 2008, the U.S. Supreme Court — for the first time in nearly 70 years — decided a case squarely addressing the meaning of the Second Amendment. In District of Columbia v. Heller, the Supreme Court concluded that the Second Amendment protected an individual right to own handguns in the home, invalidating a Washington, D.C. law.
But Heller left many issues undecided, including the precise scope of the Second Amendment.