But there were some very courageous people who did openly dissent. My mother's uncle (John Caughlan) was first kicked out of his law firm and shortly thereafter the ACLU for standing up and saying that the Communist Party USA had Constitutional rights too and they should be defended (and defend them he did for which he earned a year in prison but did not lose his license to practice law and continued the fight pretty much up until his death).

There is an interesting interview with him at http://depts.washington.edu/labhist/cpproject/caughlan_inter...

It is worth noting that our strong protections of open dissent were specifically created by the court in response to very dramatic overreaches by the government.