District of Columbia v. Heller - 554 U.S. 570, 128 S. Ct. 2783 (2008)
RULE:
Like most rights, the right secured by the Second Amendment is not unlimited. From Blackstone through the 19th-century cases, commentators and courts routinely explained that the right was not a right to keep and carry any weapon whatsoever in any manner whatsoever and for whatever purpose. Nothing in the Supreme Court's Heller opinion should be taken to cast doubt on long-standing prohibitions on the possession of firearms. The Supreme Court identifies presumptively lawful regulatory measures only as examples; the list does not purport to be exhaustive.
CONCLUSION:
The Court held that the Second Amendment protected an individual right to possess a firearm unconnected with service in a militia and to use that firearm for traditionally lawful purposes, such as self-defense within the home. The Court determined that the Second Amendment's prefatory clause announced a purpose but did not limit or expand the scope of the operative clause. The operative clause's text and history demonstrated that it connoted an individual right to keep and bear arms, and the Court's reading of the operative clause was consistent with the announced purpose of the prefatory clause. None of the Court's precedents foreclosed its conclusions. The Court held that the Second Amendment right was not unlimited, and it noted that its opinion should not be taken to cast doubt on certain long-standing prohibitions related to firearms.
The SCOTUS ruling
5-4.