36 U.S.C. § 301 — National anthem

(a) Designation — The composition made up of the words and music known as the Star-Spangled Banner is the national anthem. (b) Conduct During Playing — During a rendition of the national anthem: (1) When the flag is displayed — (A) individuals in uniform should give the military salute at the first note of the anthem and hold that position until the last note; (B) members of the Armed Forces and veterans present but not in uniform may render the military salute the same way people in uniform do; and (C) everyone else present should face the flag and stand at attention with their right hand over their heart, and men not in uniform, if wearing a hat, should remove it with their right hand and hold it at their left shoulder, over their heart. (2) When the flag is not displayed, everyone present should face toward the music and act the same way they would if the flag were displayed. This subsection uses the word "should," not "must," so it describes expected conduct rather than a legal requirement.