I don't see why any politician or public figure should be afforded one iota more or less protection under the law, so my feeling is, if it's protected speech against anyone at CC, DU, or anywhere else, it should be protected speech against Bush, Obama, etc.
Converse is true, imo, if it's considered a threat punishable by law against a president, and someone makes a comment like that against a private citizen, that person ought to be criminally charged as well.
I personally don't find this free speech, and wouldn't regardless of WHO the victim is.