Mark Blaug as a young tutor at Queens College in New York, endorsed a student petition protesting the firing of a left-wing tenured professor for having refused to co-operate with the Un-American Activities Committee. Less than a day later, Blaug received a note from the President of Queens College, telling Blaug that his choice was either to resign or be fired. He resigned.
Fortunately, he received a grant from the Social Science Research Council to complete his dissertation, after which, again seeking employment, he obtained a job interview at Yale:
(p. 77) In the course of the interview, I felt impelled to explain how I had lost my previous teaching position at Queens College. I always remember how Fellner cut me off, saying: ‘We don’t want to hear about that. This is a private college and what transpired at a public university a few years ago is of no concern to us.’ I never had a better demonstration of Milton Friedman’s thesis that a free market, by multiplying the number of probable employers, is more likely to secure liberty for the individual than a socialist system in which the state is a monopsonist.
Blaug, Mark. “Not Only an Economist: Autobiographical Reflections of a Historian of Economic Thought.” In Reflections of Eminent Economists, edited by Michael Szenberg and Lall Ramrattan, 71-94. Cheltenham, UK: Edward Elgar, 2004.