Should we be worried?

Last Friday (Jan. 5), a bit of news that could affect everybody seemed to get very little coverage.
Just before Congress' Christmas break, President Bush's signed a standard piece of postal legislation. The bill doesn't seem to be that important, but what has raised questions is Bush's signing statement interpreting the newly passed law.
The statement sets up a pretty broad set of circumstances in which mail could be opened and searched without a warrant. Though the statement is really just a suggestion, it can shape the way a law is enforced.
The ACLU is outraged and the American Bar Association notes that Bush has issued more signing statements than all other presidents combined and his actions are hurting the separation of powers set up in the Constitution.
In the past few years, American citizens believed to be involved in terrorist actions have been held indefinitely without being charged, denied access to the outside world, including legal counsel, and tried in military courts instead of by juries of their peers; in some cities, security cameras record everything that happens on public thoroughfares; and some believe the government has listened to private citizens' phone calls without warrants.
In an era in which fear of terrorism is pervasive and the country is at war, how much should we sacrifice to be safe and how will we know if things have gone too far?