About a century ago, there was a tussle in higher education policy about the freedom of professors to express opinions. Academic tenure was not yet well-established, and so the prospect of professors being fired because they openly disagreed with someone in academic or political power were quite real. In 1915, the “General Report of the Committee on Academic Freedom and Academic Tenure” was presented at the annual meetings of the American Association of University Professors. It was published in the Bulletin of the American Association of University Professors (December 1915, pp. 15-43), and is readily available through the magic of HathiTrust.
In my reading, the report sought to strike a balance. It affirmed in strong terms that professors had a right to speak out, conclude what they wanted from their research, write what they wanted, join political movements,and so on. However, it also stated that professors should either forebear or be cautious, in several specific contexts, from expressing political opinions. In particular, the report argued against professors bringing their political beliefs into the classroom or into the institutional purpose of the university. To put it another way, part of the tradeoff for the freedom and security of academic tenure in the personal sphere was an assumption of responsibility that the university itself not take overtly or excessively partisan positions, whether officially or in its classrooms. It also argued that this standard should be enforced by other faculty members.