The United States Flag Code establishes advisory rules for display and care of the national flag of the United States of America. It is Chapter 1 of Title 4 of the United States Code (4 U.S.C. § 1 et seq). This is a U.S. federal law, but the penalty described in Title 18 of the United States Code (18 U.S.C. § 700) for failure to comply with it is not enforced. In 1990, the U.S. Supreme Court ruled in United States v. Eichman that prohibiting burning of the U.S. flag conflicts with the First Amendment right to freedom of speech and is therefore unconstitutional.
This etiquette is as applied within U.S. jurisdiction. In other countries and places, local etiquette applies.
The flag is specifically authorized to be flown 24 hours a day at certain locations:
At other locations, it is flown continuously by custom, including:
Out of practical necessity, five of the six U.S. flags standing on the moon (the Apollo 11 flag was blown over during departure) fly continuously, even during the two-week lunar night.
All such conduct toward the flag in a moving column should be rendered at the moment the flag passes.
A later amendment further authorized hand-salutes during the national anthem by veterans and out-of-uniform military personnel. This was included in the Defense Authorization Act of 2009, which President Bush signed on Oct. 14, 2008. Public Law 113-66, enacted on 26 December 2013, reaffirmed this authorization.
Prior to Flag Day, June 14, 1923, neither the federal government nor the states had official guidelines governing the display of the United States' flag. On that date, the National Flag Code was constructed by representatives of over 68 organizations, under the auspices of the National Americanism Commission of the American Legion. The code drafted by that conference was printed by the national organization of the American Legion and given nationwide distribution.