Central Hudson Gas & Electric Corp. v. Public Service Commission, 447 U.S. 557 (1980), was an important case decided by the United States Supreme Court that laid out a four-part test for determining when restrictions on commercial speech violated the First Amendment of the United States Constitution. Justice Powell wrote the opinion of the court. Central Hudson Gas & Electric Corp. had challenged a Public Service Commission regulation that prohibited promotional advertising by electric utilities. Justice Brennan, Justice Blackmun, and Justice Stevens wrote separate concurring opinions, and the latter two were both joined by Justice Brennan. Justice Rehnquist dissented.