One mystery solved. Why was Gen. Wesley K. Clark's early removal from his post as NATO's top commander leaked within an hour after Clark himself was informed of Defense Secretary William S. Cohen's decision last Tuesday?

Answer: Because Cohen's staff wanted to prevent Clark, who had led the NATO military campaign against Yugoslavia and was known to like his job, from working behind the scenes to undo the decision, according to a senior Pentagon official.

"They decided to prevent it," said the official. "It was a brillant, effective and ruthless way of doing it, but not our preferred way of doing it." Included in the cabal that engineered the plot was Pentagon spokesman Kenneth Bacon, the official said.

"I don't really have anything to add," Bacon said yesterday.

Cohen, who clashed with Clark during the war over the four-star's desires to plan for a ground invasion, made the decision to remove Clark early and without consulting him beforehand, because he wanted to find a way to keep Gen. Joseph W. Ralston, the vice chairman of the Joint Chiefs of Staff. Ralston, set to retire next year, said the NATO post was the only job he wanted.

Secretary of State Madeleine K. Albright, a Clark fan, was appalled at the treatment, and President Clinton later expressed disappointment at the Pentagon's handling of the matter.

Clark, who is set to leave in April, is not the only top general leaving soon. The other moves will begin in December, when Gen. John Tilelli, commander of the combined U.N.-U.S. forces in South Korea, will be replaced by Gen. Thomas Schwartz, now commander of the U.S. Army Forces Command.

After that, Adm. Harold W. Gehman Jr., head of the U.S. Atlantic Command will retire, to be followed by Marine Corps Gen. Anthony C. Zinni, now the commander of the U.S. Central Command, for which the main preoccupation these days has been Iraq.

Following on Zinni's heels will be Marine Corps Gen. Charles C. Wilhelm, head of the U.S. Southern Command, which overseas U.S. military operations in South America and Central America.

Adm. Richard Mies will then leave as commander of the U.S. Strategic Command, which oversees the U.S. nuclear arsenal. And finally, out goes Gen. Peter J. Schoomaker, head of the U.S. Special Operations Command.

AWARDING SECRETS: Every year, the Defense Department loves to broadcast the recipients of the President's Quality Award program as a way to show that even the bureaucracy known for its $500 screwdrivers can make improvements and be an innovator. This year, one of the awards went to the secretive National Security Agency and its Central Security Service. According to the DOD announcement on July 23, the agency "was recognized for improving delivery time of vital time-sensitive information to the President and the National Security Council."

What does that mean, exactly?

The department's full-time Quality Awards coordinator, Tom Laccone, was very friendly, but he couldn't say much about the award because the NSA took the application back. It was classified.

As Laccone recalls, though, one of the achievements was cutting from five to two minutes the time it takes for the NSA to get a certain type of urgent information to the NSC.

The NSA public affairs officer was pleasant but wanted a list of questions faxed over. Wouldn't an e-mail do? "Sorry, we don't have e-mail." Okay . . .

So the faxed question was this: "What did you win this award for? Please be as specific as possible." After 24 hours, the answer can back: "We are unable to provide any specific examples because of the classified nature of our operations and of the information we provide to the President and NSC."

However, she did send over some hints: Among the improvements the NSA and the CSS submitted on their application for the award was the fact that the delivery time of "vital, sensitive information" to the president and NSC had been reduced "by 50 percent." They also saved more than $12 million by reusing "key storage devices that enable telephone units to operate in a secure mode."

THE REMAINS OF WAR: U.S. warplanes dropped 1,100 cluster bombs during Operation Allied Force against Yugoslavia, says the Defense Department. Each contained 202 bomblets. That's 222,200 bomblets each. With a dud rate of 5 percent, it is likely, a DOD spokesman said, that about 11,110 bomblets are sitting around unexploded.