[dilpo]

Actually you have a point about this being a violation of his civil rights. I went to the college web site and found it's "diversity policy". Here it is:

Smith College does not discriminate in its educational and employment policies on the bases of race, color, creed, religion, national/ethnic origin, sex, sexual orientation, age, or with regard to the bases outlined in the Veterans Readjustment Act and the Americans with Disabilities Act.

Notice it includes "creed" here. Here is a definition of "creed":

(from Cambridge Advanced Learner's Dictionary)
creed noun [C] (ALSO credo) FORMAL
a set of beliefs which expresses a particular opinion and influences the way you live

So it looks to me like denying tenure due to one's political or social beliefs is discrimination on account of creed and it violates their own anti discrimination policy.

[friendly]

This absolutely is discrimination of the most extreme nature. Conservatives are ferociously blacklisted.