You touch on an interesting point.
I believe people are willing to concede certain liberties if they are in exchange for better communities / safer environments, etc.
Lately it seems as if people are being asked to concede these liberties with no guarantees that their concessions are going to improve their lives. In fact many times it seems that these "improvements" don't do anything to improve public safety.
I don't the government refuses to protect national security, I don't think they're capable.
Frankly if we took that money and used it to build business / schools improve standards of living in "terrorist" nations, that would go a lot farther than "national security" in keeping the country safe.