John Derbyshire mentions in passing Edward Alsworth Ross (1866-1951), an old leftist professor of sociology who had a tumultuous public life that would be incomprehensible to today’s left. From Wikipedia:

In Stanford’s “first academic freedom controversy,” Ross was fired from Stanford because of his political views on eugenics. He objected to Chinese immigrant labor (on both economic and racial grounds: he was an early supporter of the “Race Suicide” doctrine and expressed his hatred of other races in strong and crude language in public speeches[citation needed]) and Japanese immigration altogether. …

In response, Jane Stanford called for his resignation. … The position was at odds with the university’s founding family, the Stanfords, who had made their fortune in Western rail construction, a major employer of coolie laborers.

Ross had also made critical remarks about the railroad industry in his classes: “A railroad deal is a railroad steal.” This was too much for Jane Stanford, Leland Stanford’s widow, who was on the board of trustees of the university. Numerous professors at Stanford resigned after protests of his dismissal, sparking “a national debate… concerning the freedom of expression and control of universities by private interests.” The American Association of University Professors was founded largely in response to this incident.

Ross visited Russia after the Bolshevik Revolution in 1917. He endorsed the revolution even as he acknowledged its bloody origins. He was subsequently a leading advocate of US recognition of the Soviet Union. However, he later served on the Dewey Commission, which cleared Leon Trotsky of the charges made against him by the Soviet government during the Moscow Trials.

From 1900 to the 1920s, Ross supported the alcohol Prohibition movement as well as continuing to support eugenics and immigration restriction. By 1930, he had moved away from those views, however.

In the 1930s, he was a supporter of the New Deal programs of President Franklin Roosevelt. In 1940, he became chairman of the national committee of the American Civil Liberties Union, serving until 1950.