Zechariah Chafee Jr. (December 7, 1885 – February 8, 1957) was an American judicial philosopher and civil rights advocate, described as "possibly the most important First Amendment scholar of the first half of the twentieth century" by Richard Primus.

[2] Chafee was born in Providence, Rhode Island,[3] and graduated from Brown University, where he was a member of Alpha Delta Phi, in 1907.

Inspired by the United States' suppression of radical speech and ideas during the First World War, Chafee edited and updated a collection of several of his journal articles.

When President Roosevelt signed the Smith Act into law in 1940, which raised the penalties for alleged sedition, Chafee characterized it as “one of the most drastic restrictions on freedom of speech ever enacted in the United States during peace.

Once the sword is placed in the hands of the people in power, then, whatever it says, they will be able to reach and slash at almost any unpopular person who is speaking or writing anything that they consider objectionable criticism of their policies.”[8] Chafee revised and reissued this work in 1941 as Free Speech in the United States, which became a leading treatise on First Amendment law.

Chafee met with Justice Holmes after the Schenck case 249 U.S. 47 (1919), which upheld a conviction of an activist who encouraged draft resistance, and convinced him that free speech needed greater consideration.

In (West Virginia State Board of Education v. Barnette,319 U.S. 624 (1943) Chafee submitted a amicus curiae brief to the Supreme Court hoping to persuade the Court to reverse an earlier decision[10] upholding a state law requiring a salute to the flag by children of Jehovah's Witnesses based in the principles of freedom of speech and freedom of religion.

At the request of Senator Burton K. Wheeler, Chafee urged the Bill of Rights Committee to take a public stand against the Sedition of Trial of 1944.

The commission was established in 1943 by Henry Luce to determine if freedom of the press was in danger in the United States and was chaired by Robert Maynard Hutchins.

Chafee became an advocate for international human rights through his work as a representative on the United Nations Subcommission on Freedom of Information and the Press in 1947 through 1951.