The president acknowledged the surveillance in his regular radio address Dec. 15.

Mr. Bush said he has no regrets about authorizing the NSA to monitor telephone conversations and e-mails from within the U.S. -- all of which, he says, involved suspected terrorists overseas.

The 1978 Foreign Intelligence Surveillance Act sets up a system requiring judicial approval before such surveillance can be conducted. But Mr. Bush authorized these wiretaps without a warrant. He and Vice President Dick Cheney say the eavesdropping is consistent with the law and that members of Congress were briefed. Mr. Bush said last week he “absolutely” has the power to authorize the wiretaps under the Constitution and statutes passed following the Sept. 11 terrorist attacks.

“This is a different era, a different war,” Bush said. “This is where people are changing phone numbers and phone calls and moving quick. It requires quick action.”

The eavesdropping is “limited,” Bush said, aimed at “people with known links to al-Qaida.”

The president then proceeded to call the disclosure of his eavesdropping “a shameful act.”

In fact, leaving aside for the moment whether the Constitution grants either the president or the Congress the powers here claimed (and their oaths to “protect and defend” the Sixth Amendment would appear to constitute a sizeable counter-indicator), in a free country it is the act of concealing such domestic spying -- thus preventing it from becoming the subject of a healthy public debate -- which is shameful.

Yes, in some hypothetical scenario, a news organization might be justified in agreeing to withhold details of a story for a brief time in order to, say, help foil another bombing attack. But the New York Times sat on this story for a year. Newspapers are not in the job of saying, “Here’s some breaking news about the causes of the Spanish-American war which we agreed to keep under wraps for a century so as not to embarrass anyone.”

Calling a newspaper “shameful” for merely doing its job, exposing unpleasant truths about potentially unconstitutional or illegal government actions and letting the public debate begin, shows a tin ear for legitimate concerns about the erosion of privacy and government overstepping its bounds, to say the very least.

There is little doubt these revelations are strengthening Senate forces that oppose re-authorization of the Patriot Act.

Indeed, those so-called “obstructionist” senators are right to ask whether the Patriot Act’s sweeping provisions are truly necessary to fight terrorism, whether they erode our freedoms or extend govenrment power beyond the firm limits set by the Founders (a question which trumps any mere argument of utility), and whether they are even the least onerous, least freedom-jeopardizing ways to get the job done.

Claims of “operational secrecy” cannot provide cover forever. It’s been four years since Sept. 11 -- Eisenhower didn’t need that long to plan the invasion of France.

Nor does, “It’s worked; there have been no more terror attacks” hold much water. Lacking more specific examples, the same argument could hold that measles vaccinations have prevented further terror bombings.

Senator Arlen Specter, appearing on CNN’s “Late Edition” Sunday, said the Judiciary Committee he leads will hold hearings on the issue. “There are limits to what the president can do under the Constitution,” said the Pennsylvania Republican. “Whether it was legal is a matter that ought to be examined.”

Sen. Russell Feingold, Democrat of Wisconsin, called the eavesdropping “an outrageous power grab.” When Congress passed a resolution to invade Afghanistan and fight the war on terror, nobody thought “this was an authorization to allow a wiretapping against the law of the U.S.,” Sen. Feingold said on NBC’s Monday “Today” program.

Sen. Feingold, a newly reborn fan of sharply limited government, displays his typical statesmanlike reserve. But in substance, both senators are correct. Congress has an oversight duty, here. No president -- judge his intentions as you will -- can be allowed to simply say, “What I’m doing is constitutional but I’m not going to tell you about it; you just have to trust me.”

Down that road lies tyranny.

And it is certainly not reassuring when the president’s men continue to indulge in what looks for all the world like legalistic hair-splitting.

Attorney General Alberto Gonzales, at a news conference Monday, said the electronic surveillance is limited in its application and applies only when “one party to the communication is outside the U.S.”

Funny; I can’t find that exemption anywhere in my copy of the Fourth Amendment. Shall we next ban membership in churches headquartered “outside the United States?”

A thorough -- and thoroughly public -- congressional investigation is called for. And the president should cooperate fully, no matter how such demands of a constitutional republic may try his patience.

Consider it “a good example to the Iraqis.”