What was this case about?

The Constitution's Second Amendment, 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."

This court ruling affirmed Congress' right to regulate firearms that are not related to preservation or efficiency of a militia.

Background on the case

Jack Miller and Frank Layton were convicted of illegally transporting "a certain firearm, to-wit, a double barrel 12-gauge Stevens shotgun having a barrel less than 18 inches in length" from Oklahoma to Arkansas.

They appealed - claiming the law they violated, the National Firearms Act, was unconstitutional because it "is not a revenue measure but an attempt to usurp police power reserved to the States." They also claimed it violated the Second Amendment.

Decision

The participating justices unanimously ruled that the Second Amendment applies solely to militias.

The signification attributed to the term Militia appears from the debates in the Convention, the history and legislation of Colonies and States, and the writings of approved commentators. These show plainly enough that the Militia comprised all males physically capable of acting in concert for the common defense. 'A body of citizens enrolled for military discipline.' And further, that ordinarily when called for service these men were expected to appear bearing arms supplied by themselves and of the kind in common use at the time.

They also wrote that the Second Amendment does not provide a blanket guarantee for any type of weapon.

"In the absence of any evidence tending to show that possession or use of a 'shotgun having a barrel of less than eighteen inches in length' at this time has some reasonable relationship to the preservation or efficiency of a well regulated militia, we cannot say that the Second Amendment guarantees the right to keep and bear such an instrument."