No man loathed leaks more than William J. Casey, the late director of the CIA.

He wanted to polygraph the whole government. He hated for people to write books about the agency. He often didn't tell Congress what he was doing for fear they would blab.

Now comes Bob Woodward, the inexorable investigative ace of The Washington Post, who with his partner Carl Bernstein pushed Casey's friend Richard M. Nixon out of the presidency, to tell us Casey talked to him no less than 48 times over the last three years, telling him things that Sam Nunn (D-Ga.), a member of the Senate intelligence committee, complains, "He never told us."

Congress, which liked to think it oversaw Casey, cannot take it in.

"If any of us told these things," said Louis Stokes (D-Ohio), chairman of the House intelligence committee, "we would be indicted."

Another committee member, who did not wish to be named, said, "Woodward was the enemy. Why did Casey invite him to ride on his airplane and talk to him without the presence of another person, or a note-taker, and run the risk of being seen with him at the airport?"

It is indeed hard to fathom, but not without precedent. David A. Stockman, the former Reagan budget director, succumbed to the same strange compulsion to confess to an unsympathetic outsider. He met regularly with William Greider, then an assistant managing editor of The Post, and confided his disdain for the supply-side economics being offered by the administration. Apparently both Casey and Stockman wanted someone sensible to judge their follies.

Woodward reports that when Casey lay on his deathbed he slipped past CIA guards outside Casey's hospital room and spent enough time with Casey to extract a confession that he knew about the diversion of Iranian arms profits to the Nicaraguan contras. Sophia Casey, the director's widow, calls Woodward's account "untrue . . . a lie."

Meantime, the central point seems to go unremarked. What Woodward is providing is corroboration of Lt. Col. Oliver L. North's Iran-contra hearings testimony that Casey dreamed of the day when he would have at his command an "off-the-shelf, . . . full-service covert operation."

The operation aimed at assassinating Sheik Mohammed Hussein Fadlallah, a Shiite terrorist, was financed by Saudi money, with the $3 million transaction personally arranged by Casey and the Saudi ambassador, Prince Bandar bin Sultan. Fadlallah escaped the car bombing of March 1985, but 80 innocent bystanders died.

"It fits like a hand in a glove the testimony of Ollie North," said Arthur L. Liman, chief counsel of the Senate Iran-contra committee.

A wisp of legality was thrown over the attempt by an "antiterrorist" finding signed by the president. It contained vague language about "preemptive self-defense." But as Warren B. Rudman (R-N.H.), a member of the Senate Iran-contra committee, pointed out, the finding was directed at preventing terrorist action, which he described as retribution, Casey's answer to the truck bombing of the Marine barracks in October 1983. And no finding could supersede the absolute prohibition against assassination that is contained in an executive order the president signed soon after he took office.

A footnote shows Casey's buccaneering style: the sheik was bought off for $2 million. Car bombings ceased.

In due course, discussion will turn to the question of how much the president knew about the Fadlallah assassination attempt and when he knew it. The White House isn't talking.

The question that should be asked -- and almost certainly won't be -- is, is it time to outlaw covert actions?

In 1976, the Church committee told us how the CIA abused its "covert capability," as they call it, in wholesale and appalling fashion. There was the infamous drug experiment program, in which LSD was given to unsuspecting citizens; the huge, forbidden domestic spying project, called Operation Chaos; the subversion of the Allende government in Chile; countless assassination attempts against Fidel Castro, and ad lib interference in the affairs of nations all over the world.

The Church panel showed how the CIA as an agency turned into a "rogue elephant." The Iran-contra hearings provided a sequel about illegal activities transferred to the National Security Council, which ran a clandestine war. Woodward shows how one old man with a strong will and foreign funds could laugh at the law and shake up the world.

But not a single voice was raised against covert action at the hearings. A rattlesnake, yes, but we need it around the house. Give it rules, and it will do no harm. It's a story that's wearing thin.