It could be according to the United States Court of Appeals for the Fourth Circuit. A sheriff’s deputy supported the Sheriff’s opponent and “liked” the Facebook page of his opponent. Of course, the sheriff won re-election and the deputy who supported his opponent was terminated. The Court ruled that “liking” a candidate on the internet is the internet equivalent of displaying a political sign in one’s front yard which the Supreme Court has ruled is protected speech.
See Bland v. Roberts at http://www.ca4.uscourts.gov/Opinions/Published/121671.P.pdf