The "marketplace of ideas" is a pervasive meme in the US. I was familiar with it in the context of one Supreme Court ruling regarding academic freedom, but I just found this:

The philosophical core that Justice Oliver Wendell Holmes inserted into the freedom of speech debate over 78 years ago continues to beat like a young heart in the body of First Amendment law. His words were at the center of the U.S. Supreme Court's reasoning when on June 26 in Reno v. American Civil Liberties Union, it struck down the Communications Decency Act as a violation of the Constitution.

In 1919, Justice Holmes filed a dissent in Abrams v. United States in which he created the powerful and enduring "marketplace of ideas" metaphor to encapsulate the concept of freedom of speech. In the marketplace metaphor, ideas compete against one another for acceptance -- with the underlying faith that truth will prevail in such an open encounter.

Borrowing from John Milton's "Areopagitica" (1644) and John Stuart Mill's "On Liberty" (1859), Holmes wrote in his Abrams dissent: "But when men have realized that time has upset many fighting faiths, they may come to believe even more than they believe the very foundations of their own conduct that the ultimate good desired is better reached by free trade in ideas -- that the best test of truth is the power of the thought to get itself accepted in the competition of the market ... . That at any rate is the theory of our Constitution. It is an experiment, as all life is an experiment."

Justice Holmes' pivotal concept gradually became the controlling metaphor in First Amendment jurisprudence. His voice was present in the high court's decision striking down the CDA.

A society committed to the notion that government is always bad will have bad government. And it doesn't have to be that way. — Paul Krugman