Advertising is indeed protected by the First Amendment of the U.S. Constitution. Advertising or "Commercial speech" enjoys somewhat less First Amendment protection from governmental encroachment than other types of speech. The Federal Trade Commission, for example, may regulate speech that is found to be "deceptive."
Under the landmark U.S. Supreme Court decision, Central Hudson Gas & Electric Corp. v. Public Service Commission Of New York, No. 79-565, Supreme Court Of The United States, 447 U.S. 557; 100 S. Ct. 2343; 1980 U.S. LEXIS 48; 65 L. Ed. 2d 341; 6 Media L. Rep. 1497; 34 P.U.R.4th 178, June 20, 1980, a state must justify restrictions on truthful, nonmisleading commercial speech by demonstrating that its actions "directly advance" a substantial state interest and are no more extensive than necessary to serve that interest. This is the so-called Central Hudson Test.
Commercial speech now clearly has a prominent place in the rights protected by the First Amendment. A 1993 Supreme Court opinion summarized the general principles underlying the protection of commercial speech:
"The commercial market place, like other spheres of our social and cultural life, provides a forum where ideas and information flourish. Some of the ideas and information are vital, some of slight worth. But the general rule is that the speaker and the audience, not the government, assess the value of the information presented. Thus, even a communication that does no more than propose a commercial transaction is entitled to the coverage of the First Amendment." (Edenfield v. Fane, 123 L. Ed. 2d 543, 113 S. Ct. 1792, 1798 (1993).)
The following is the full text of the U.S. Supreme Court decision in Rubin v. Coors Brewing Co. (93-1631), 514 U.S. 476 (1995).
NOTICE: This opinion is subject to formal revision before publication in the preliminary print of the United States Reports. Readers are requested to notify the Reporter of Decisions, Supreme Court of the United States, Washington, D.C. 20543, of any typographical or other formal errors, in order that corrections may be made before the preliminary print goes to press.