ASHINGTON
Under the police powers it operated under last year, and with the lawful cooperation of a better-managed C.I.A., an efficiently run F.B.I. might well have prevented the catastrophe of Sept. 11. That is the dismaying probability that Congressional oversight (it should be called undersight) will begin to show this week.

To fabricate an alibi for his nonfeasance, and to cover up his department's embarrassing cut of the counterterrorism budget last year, Attorney General John Ashcroft working with his hand-picked aide, F.B.I. Director "J. Edgar" Mueller III has gutted guidelines put in place a generation ago to prevent the abuse of police power by the federal government.

They have done this deed by executive fiat: no public discussion, no Congressional action, no judicial guidance. If we had only had these new powers last year, goes their posterior-covering pretense, we could have stopped terrorism cold.

Not so. They had the power to collect the intelligence, but lacked the intellect to analyze the data the agencies collected. The F.B.I.'s failure to absorb the Phoenix and Minneapolis memos was compounded by the C.I.A.'s failure to share information it had about two of the Arab terrorists in the U.S. who would become hijackers (as revealed by Newsweek today).

Thus we see the seizure of new powers of surveillance is a smokescreen to hide failure to use the old power.

Ashcroft claims he is merely allowing the feds to attend public events, or to surf the Internet, which "even a 12-year-old can do." That's a masterful deceit: under the former anti-abuse guidelines, of course the F.B.I. could send an agent into a ballpark, church or political rally. All it needed was "information or an allegation whose responsible handling required some further scrutiny" not even "probable cause" to investigate a crime, but a mere tip about possible wrongdoing.

Same with surfing the Net or reading a newspaper or watching television news. Often that's how F.B.I. agents in the field have been alerted to a potential crime, and could then open a preliminary inquiry. If a lead showed "reasonable indication of criminal activity," agents could initiate a full investigation without going through Washington headquarters hiring informants, staking out a house, seeking wiretap and search warrants.

But under the new Ashcroft-Mueller diktat, that necessary hint of potential criminal activity is swept away. With not a scintilla of evidence of a crime being committed, the feds will be able to run full investigations for one year. That's aimed at generating suspicion of criminal conduct the very definition of a "fishing expedition."

Not to worry, say governmental perps we won't collect data in dossiers on individuals or social or political clubs or church groups the sort of abuse that suppressed dissent in "the bad old days."

Just because the F.B.I. brass hats are presently computer illiterate, do they think the public is totally ignorant of the ability of today's technologists to combine government surveillance reports, names on membership lists, and "data mining" by private snoops to create an instant dossier on law-abiding Americans?

Consider the new reach of federal power: the income-tax return you provided your mortgage lender; your academic scores and personnel ratings, credit card purchases and E-ZPass movements; your political and charitable contributions, charge account at your pharmacist and insurance records; your subscription to non-mainstream publications like The Nation or Human Events, every visit to every Web site and comment to every chat room, and every book or movie you bought or even considered on Amazon.com all newly combined with the tickets, arrests, press clips, full field investigations and raw allegations of angry neighbors or rejected lovers that flow into the F.B.I.

All your personal data is right there at the crossroads of modern marketing and federal law enforcement. And all in the name of the war on terror.

This is not some nightmare of what may happen someday. It happened last week. Jim Sensenbrenner, chairman of House Judiciary, said the removal of restraints made him "queasy"; Pat Leahy of Senate Judiciary is too busy blocking judges to object. Some sunshine libertarians are willing to suffer this loss of personal freedom in the hope that the Ashcroft-Mueller rules of intrusion may prevent a terror attack. They won't because they're a fraud.