In speaking with a large group of student interns on Capitol Hill recently — students from across the country and the ideological spectrum — I asked a simple question: "When you communicate with others by e-mail, do you consider your communications private?"

All raised their hands in the affirmative. I asked a follow-up question: "Do you think the government should have the right to 'listen in' to those Internet communications?" Virtually all the students raised their hands in the negative. I asked a final question: "Do you think the government does 'listen in' to those private communications?" About half raised their hands in the affirmative.

When I informed the students that the government, in the wake of the terrorist attacks of Sept. 11, 2001, not only has the power to intercept and read private Internet communications of U.S. citizens without a court order, but does so routinely, the students were visibly stunned. As well they should be.

You know, there was a time not all that long ago in America when it was a commonly accepted notion — backed by the courts — that the government could not eavesdrop on a citizen's private communication, whether by phone or mail or, later, by computer, without a pretty good reason for doing so. That meant a government agent would have to go to a federal judge and lay out the case for why the citizen's privacy should be invaded.

The government would be forced to answer such questions as, "What criminal behavior is the citizen engaged in? Is this intrusion absolutely essential? Isn't there a less intrusive means of gathering this evidence? Will the government strictly limit the scope and duration of the intrusion?"

There was also a time, only a year and a half ago, when the government, in executing a search warrant, would have to give the home or business owner contemporaneous notice that the search was going to be conducted. The government would also have to hand the person an inventory of what the government agents had seized.

These two requirements, which the government had to follow absent exigent circumstances (emergency, destruction of evidence likely, etc.), simply gave the citizen knowledge necessary to contest the facts of the search or seizure. The citizen could thus assert any constitutional infirmities in the government's behavior.

Obviously, in the absence of notice and inventory, the constitutional guarantee in the Fourth Amendment that the citizen (or noncitizen alike) be free from unreasonable searches and seizures would be meaningless. If you don't know your home or office has been searched, if you don't know what the government has taken, then you have no way to know if your constitutional rights have been violated.

There was also a time, not long ago, when the government could not declare a domestic anti-abortion or pro-gun rights group a "domestic terrorist organization" and prosecute a citizen for simply sending contributions to such organizations.

You used to be able to go to a public library, check out whatever books you desired, or use a computer and review whatever lawful sites you wished to visit, and leave the library with the secure knowledge that the librarian would not rat on you to the government about what you were reading, at least not without a valid court order.

Guess what? The future is here. Thanks to the USA Patriot Act and other post-9-11 legislation and federal regulations, these and other "quaint" notions of privacy are gone.

Now, the government can engage in "sneak and peek" — that is, notice-less searches and seizures — virtually any time it wants; and not just in cases involving terrorism. It can engage in the other activities mentioned above. Try traveling on a plane. Even after going through reasonable and appropriate metal and explosive-detection devices, you are singled out for a public, partial strip search. The reason? Perhaps nothing more than looking at a guard the wrong way. Or not thanking the guard sufficiently for the initial search. Or because the guard noticed a "suspect" magazine in your possession.

Such personal searches can, and do, result in completely arbitrary denial of your fundamental right to travel. In much the same way, other types of warrantless searches, such as video cameras on street corners, can lead to criminal charges.

The fact is, we have rendered virtually meaningless the Fourth Amendment's prohibition against government collecting evidence on law-abiding citizens unless there is reason to suspect the citizen engaged in criminal behavior. And, if that worries you, as it should, wait until the next chapter — the proposed "Son of Patriot Act" — is written.

Bob Barr is a former CIA official, U.S. attorney and Republican congressman from Georgia. He is now a distinguished fellow with the Freedom Alliance in Dulles, Va., and a special consultant to the ACLU.