Now we know for sure what we knew all along. Thanks to a colorful outburst by Lawrence Wilkerson, former secretary of state Colin Powell's chief of staff, the full dimensions of how "dysfunctional" (his word) the national security apparatus was during President Bush's first term are clearer than ever. Any residual effort to present the rift between Powell and Vice President Cheney and Defense Secretary Donald Rumsfeld as a series of minor disagreements should be dead, given Wilker- son's closeness -- on a day-in and day-out basis -- to Powell. In fact, the speech should remind journalists that they failed to dig enough; the outlines of the high-stakes struggle were widely known but vastly underreported; administration denials, including disingenuous State Department denials, were routinely publicized as fact, and billed equally with reports of friction. But, according to Wilkerson (and many others), it wasn't Washington's usual bureaucratic friction; it was war.

Wilkerson's brutal attack on what he called the "Cheney-Rumsfeld cabal" was intended as a full-scale defense of his former boss. But what he shows is something quite different.

In a rambling presentation to the New American Foundation on Wednesday, Wilkerson said Bush was "not versed in international relations and not too much interested either." Then Wilkerson really got down to business. Recommending George Packer's brilliant new book on Iraq, Wilkerson said that he "could have given George a hell of a lot more specifics" on how "the Cheney-Rumsfeld cabal flummoxed the system," supported by people such as Defense Undersecretary Douglas Feith ("Seldom in my life have I met a dumber man."). He added that Rumsfeld had been "given carte blanche to tell the State Department to go screw itself in a closet somewhere."

Asking himself "Who's causing this?" Wil- kerson offered a strange answer: "The national security adviser . . . who made a calculated decision to build her intimacy with the president" rather than do her job. He predicted that if there were a major terrorist attack on a U.S. city, "you are going to see the ineptitude of this government."

As George F. Will would say: Well. Wilkerson is a retired colonel who sat in the office closest to Powell's at State. While he says his decision to go public was opposed by Powell, "one of the world's most loyal soldiers" (a view not shared by the White House), it will be hard for anyone to deny that Wilkerson in large part reflects the thinking of the man he served loyally for 16 years.

I am certainly not going to defend Cheney or Rumsfeld. They made mistakes of historic proportions in Iraq and elsewhere, and the damage done to America's world role in the past four years will, I believe, take a decade to undo. But for Wilkerson to describe major policy mistakes as the result of a process that was dysfunctional -- even though it was -- is inaccurate. In the end, presidents get the advice they deserve, from the advisers they pick. Those advisers never agree completely, nor should they. Bush was surely aware that there were two views in his administration on most critical issues, but the buck stopped on his desk. Apparently, Cheney's voice was often the most influential, but Bush made the final calls. As Les Gelb wrote about Vietnam with deliberate irony, "the system worked," but it produced the wrong outcome.

Wilkerson (and, presumably, his former boss) are looking in the wrong place for the answer to the wrong question. Neither man has explained publicly what he would have done differently in Iraq and elsewhere, nor why the president apparently ignored most of their advice. The "evil influence" theory Wilkerson laid out is fun to read and surely reflects Powell's feelings, but it does not explain how a national hero universally respected for his decency and integrity, and whose approval ratings were 30 points higher than those of Bush, could lose so many of the big battles.

Powell's supporters often offer the "effective trap" explanation for why he stayed, the same one Robert S. McNamara gave for staying in the Johnson administration for two years after he had concluded that the Vietnam War was unwinnable: Things would have been much worse if he had abandoned ship.

But that argument is no more valid today than it was in 1968 (when McNamara's successor, Clark Clifford, helped turn policy around). If you think things are that bad, is your first loyalty to the president or to the nation? And would your departure make things better or worse?

Which brings us to an even deeper paradox. It is not surprising that Wilkerson lashed out at Condoleezza Rice, although he failed to note that she was serving the president as he wanted to be served. But, in recent moves rich with irony, as secretary of state she has improved many first-term policies, in such places as North Korea, Iran, Bosnia and Kosovo, and in relations with some of our major European allies. (Powell's friends say with bitterness that when he proposed similar policies, he was thwarted, in part, by her.)

Not everything is better in the second term -- confusion and mixed signals still reign in such critical areas as the United Nations and China -- and then there is Iraq. But things are looking up in foreign policy. The immensely disciplined Rice is seeking to undo damage done in the past four years without ever admitting there was any -- a nifty bit of cognitive dissonance, but one she seems determined to pull off. Events have, of course, pushed her and the president in this direction, and it is easier with Feith and Paul Wolfowitz gone. But -- and this may be the most painful irony of all -- Powell's departure opened the door to somewhat more pragmatic policies, which Bush and the "cabalists" had been opposing.

Richard Holbrooke, an ambassador to the United Nations during the Clinton administration, writes a monthly column for The Post.