The high court ruled in Presser v. Illinois, 116 U.S. 252 (1886)
"It is undoubtedly true that all citizens capable of bearing arms constitute the reserved military force or reserve militia of the United States as well as of the states, and, in view of this prerogative of the general government, as well as of its general powers, the states cannot, even laying the constitutional provision in question out of view, prohibit the people from keeping and bearing arms, so as to deprive the United States of their rightful resource for maintaining the public security, and disable the people from performing their duty to the general government..."
"It is undoubtedly true that all citizens capable of bearing arms constitute the reserved military force or reserve militia of the United States as well as of the states, and, in view of this prerogative of the general government, as well as of its general powers, the states cannot, even laying the constitutional provision in question out of view, prohibit the people from keeping and bearing arms, so as to deprive the United States of their rightful resource for maintaining the public security, and disable the people from performing their duty to the general government..."