In his dissent from the majority opinion in Abrams v. United States (upholding the Espionage Act convictions of a group of antiwar activists), U.S. Supreme Court Justice Oliver Wendell Holmes coins his famous “marketplace of ideas” phrase to explain the value of freedom of speech. He said that “the ultimate good desired is better reached by free trade in ideas … the best test of truth is the power of the thought to get itself accepted in the competition of the market.”
Over the years, Holmes’ “marketplace” concept, and the idea that more is better when it comes to competing ideas, has been a consistent theme in First Amendment cases.