George Tenet’s abrupt resignation as director of the Central Intelligence Agency opens the way for a reorganization of the entire intelligence system. The system has been plagued lately by serious failures, which are about to be itemized in detail in the reports by pending investigations by a congressional intelligence committee and by the independent commission investigating the Sept. 11 attacks.

The worst of these, of course, was the failure to sound an alert to the possibility that Osama bin Laden’s terrorist network would follow up its series of attacks abroad and here at home with a major strike using hijacked jetliners as missiles. The mistaken certainty that Saddam already had chemical and biological weapons ready to go and was well on his way to developing nuclear weapons will also be high on the list. When no sign of those weapons could be found, the chief basis for war evaporated and had to be replaced by the freeing of the Iraqi people from a ruler who was a cruel despot but hardly an imminent threat to American security.

An exchange between Mr. Tenet and President Bush, quoted in Bob Woodward’s recent book “Plan of Attack,” is a prime example of a grave misuse of intelligence leading up to the Iraq war. It amounted to pressure by a president on his chief intelligence official to distort the best evidence to support a policy decision already made and was far worse than a misstatement of the available intelligence.

Mr. Bush wanted proof that Saddam Hussein had weapons of mass destruction that were an imminent threat and constituted a cause for war. An underling delivered a yes-and-no briefing that included some reasons for doubt. Mr. Bush said that wouldn’t do and asked Mr. Tenet, “George, how confident are you?” Mr. Tenet replied, “Don’t worry, it’s a slam-dunk.”

Yet, no such weapons have been found, despite a more than year-long search.

As a way to correct such lapses, the 9-11 commission’s report, due July 26, is expected to urge the consolidation of all intelligence agencies under command of a Cabinet-level intelligence chief. Sen. John Kerry, who presumably will be Mr. Bush’s Democratic rival in the November presidential election, promptly advocated such a move. Mr. Bush has said only that “We must stay ahead of constantly changing intelligence challenges.” His commission assigned to recommend restructuring of the intelligence community won’t report until next March.

Total consolidation could have a serious drawback. Intelligence is such a shadowy, uncertain enterprise that it may require a certain competition among rival agencies. The State Department’s Bureau of Intelligence and Research often has differed from the CIA and the Defense Intelligence Agency. At the Pentagon, Secretary Donald Rumsfeld objected to the State Department’s skepticism and set up his own intelligence team to look for evidence that Saddam had weapons of mass destruction and was a terrorism partner with al-Qaida.

Disagreement can be healthy. A wise and prudent president will listen to competing intelligence findings and make judgments without pressuring analysts to agree on conclusions that will support his policies.