Some have made the argument, bordering on the frivolous, that only those arms in existence in the 18th century are protected by the
Second Amendment . We do not interpret constitutional rights that way. Just as the
First Amendment protects modern forms of communications,
e.g.,
Reno v.
American Civil Liberties Union,
521 U. S. 844, 849 (1997) , and the
Fourth Amendment applies to modern forms of search,
e.g.,
Kyllo v.
United States,
533 U. S. 27, 35–36 (2001) ,
the Second Amendment extends, prima facie,to all instruments that constitute bearable arms, even those that were not in existence at the time of the founding.