In Roy L. Bourgeois, Jeff Winder, Becky Johnson, Eric LeCompte, School of Americas Watch v. Bobby Peters, Willie L. Dozier, Consolidated Government of Columbus Georgia we find the following (via CNN):
It is quite possible that both protestors and passersby would be safer if the City were permitted to engage in mass, warrantless, suspicionless searches. Indeed, it is quite possible that our nation would be safer if police were permitted to stop and search anyone they wanted, at any time, for no reason at all. [...] [T]he Fourth Amendment embodies a value judgment by the Framers that prevents us from gradually trading ever-increasing amounts of freedom and privacy for additional security. It establishes searches based on evidence–rather than potentially effective, broad, prophylactic dragnets–as the constitutional norm.
[...] Given that we have been on “yellow alert” for over two and a half years now, we cannot consider this a particularly exceptional condition that warrants curtailment of constitutional rights. We cannot simply suspend or restrict civil liberties until the War on Terror is over, because the War on Terror is unlikely ever to be truly over. September 11, 2001, already a day of immeasurable tragedy, cannot be the day liberty perished in this country. Furthermore, a system that gave the federal government the power to determine the range of constitutionally permissible searches simply by raising or lowering the nation’s threat advisory system would allow the restrictions of the Fourth Amendment to be circumvented too easily. [emphasis added]
And that’s before they get to the First Amendment issues!