Amendment II (the Second Amendment) of the United States Constitution's Bill of Rights declares a well-regulated militia as "being necessary to the security of a free State" and prohibits infringement of "the right of the people to keep and bear arms." The meaning of the Second Amendment is one of the most misunderstood and disputed among the entire Bill of Rights.
One key controversy revolves around who is prohibited from infringement and whether the Second Amendment prohibits individual States from infringing upon this right. The most recent Supreme Court precedent, from 1875, is that the Second Amendment is only a limit on the power of the federal government, (see United States v. Cruikshank) but some people contend that it extends to state jurisdictions.
Another major point of contention is whether it protects an individual right to personal firearms or a collective State militia right. At present, two of the thirteen federal circuits have adopted an individual rights view. A Second Amendment case is currently under review by the Supreme Court (District of Columbia v. Heller), having been granted certiorari, to resolve this jurisdictional split. There is also a "modified collective" view that holds the right is protected for individuals to bear arms based on their needs while serving in a militia.
Other points of disagreement include the meaning of the militia clause and the meaning of infringement, in other words, at what point does reasonable regulation of firearms constitute infringement? All federal courts have found that reasonable firearm regulation is allowable, while an outright firearm ban is currently the subject of Supreme Court review in District of Columbia v. Heller.
