The U.S. Constitution offers very broad protections for freedom of speech. While criticizing the government, or even waving the wrong flag, could get you imprisoned in any territory under Chinese rule, your right to freedom of expression is sacrosanct under the First Amendment—until you step into your place of work, that is. While the government is not entitled to punish political dissent, in most parts of America it is perfectly legal for your boss to fire you if they happen to dislike the person you voted for in the last election.
I'm convinced that reform to "at-will" employment contracts is definitely something that should be discussed, debated, and experimented with further.