So this means we should just abandon democracy and let a dictator rule? There have always been threats - Washington DC was burned down during the War of 1812. The Confederacy made a good try at doing it again during the Civil War. We lived under the threat of nuclear anihilation during the Cold War - all without demolishing the Constitution.
Regarding demolishing The Constitution, you have nothing but rhetoric to support your paranoia. The 4th Amendment says 'no unreasonable searches'. If an American citizen is speaking with a foreign agent outside our borders that has declared war on the USA, then we darn well BETTER be finding out what their plans are. The #1 duty of our government is to protect us, protect the nation, and defend The Constitution.
Defending The Constitution requires defending our nation first...no nation, no Constitutuion. What part of that do you not understand?
During the Cold War, their were plenty of people who thought we were subverting The Constitution. Remember Frank Church? Where did all that get us? A debilitated CIA and intelligence community, which indirectly led to the wall of Gorelick, which directly led to 9-11.
Thankfully, the majority of the American people understand what GWB and Cheney and Rumsfeld and Rice are doing and support it. If you want this to be a democracy, well guess what...you lose.