1. Government always has had the responsibility to censor speech, the very fine line between what is freedom of speech and what is criminal activity has always been the issue. Believe more than one person has gone to jail, or at the very least lost their career because they shared information which was classified. Surely no one would suggest that if a dumb criminal posts a video of his crime on YouTube that the police should not have the right to review that video and arrest the individual! Believe, and justifiably so, if an individual threatened/promised to kill someone, at the very least a visit from the affected law enforcement would be in the short term future.
IMO where it gets sticky is what should result in an arrest believe the quote "freedom of speech does not mean you can cry fire in a crowded theater with no fire present and not suffer repercussions" is extremely relevant.
2. U.S. Government is already part of this trend and probably has been for decades if not since 1776 (not that big of a history buff <GRIN>) What concerns me the most is there seems to be very little safeguards in place to protect our freedom of speech from those who cry "national security trumps all"
3. Yes national security is an appropriate justification, but where it gets sticky who decides what is national security. The politician du jour? The constitution, which has required interpretation well over 16000 times? or a vote by the citizens? or???
4. Transparency, although easier said than done