This chapter traces a series of stark, occasionally stunning historical reversals by the Supreme Court in interpreting the Free Speech Clause. It highlights doctrines under which the Court treats almost all content-based regulation of speech as constitutionally suspect. That position, which draws little support from research into original constitutional understandings, reflects a commitment – increasingly embraced by conservative justices of a libertarian stripe – to the principle that the Free Speech Clause bars the government from censoring speech based on fears that the speech might prove persuasive to its audience. The resulting doctrine, which makes the United States an outlier among liberal democracies, provides robust protection for a good deal of “hate speech,” some outright lies, commercial advertising, and corporate expenditures to promote political candidates. This chapter also discusses cases that have held that the Free Speech Clause protects a right to “freedom of association” that lacks any clear textual basis. It concludes by considering cases involving speech rights in “managerial domains” in which the government performs functions, such as providing public education, that it could not perform successfully without engaging in content-based regulation of speech.