America’s intelligence system failed to see terrorist threats coming from Al Qaeda that should have been evident before 9/11, and then, after 9/11, saw terrorist threats coming from Iraq that didn’t exist. A system that doesn’t warn of real threats and does warn of unreal ones is a broken system.

A unanimous and bipartisan report of the commission established by Congress to investigate intelligence mistakes leading up to 9/11 is expected to conclude that when its report is released today. Meanwhile, a unanimous and bipartisan Senate Intelligence Committee has discredited the CIA’s prewar assessments that Iraq possessed banned chemical and biological weapons and was seeking nuclear arms. Those assessments “either overstated or were not supported by the underlying intelligence,” according to the committee. The senators blamed “a series of failures” of intelligence, such as taking circumstantial evidence as definitive proof, ignoring contrary information and relying on discredited or dubious sources. The failures occurred because of “shoddy work,” faulty management, outmoded procedures, “groupthink” and a “flawed culture.”

What to do? The White House, Congress and the Kerry campaign are all sorting through several proposals. One would create a Cabinet-level intelligence “czar” with more control over the nation’s sprawling $40-billion system for collecting and analyzing information about security threats. A second would do just the opposite – remove the CIA director from any control over other intelligence agencies and hence install a better system of checks and balances. A third proposal would fix the length of the director’s term at five to seven years, removing that position from the whim of politics. A fourth, and contrary, proposal would make the director more politically accountable to the president and Congress. Almost all the proposals would beef up American intelligence with more resources.

Some of these ideas have merit, but they don’t respond to the core lesson we should have learned: When American foreign policy is based primarily on what our spy agencies say, we run huge risks of getting it disastrously wrong.

The lesson isn’t new. American intelligence failed to foresee the split between China and the Soviet Union in 1960 and 1961 and thereafter never fully comprehended it – right up through Vietnam. Had U.S. policy been based on more direct diplomacy and less on covert operations we might have avoided that shameful and costly war.

The CIA was also notoriously wrong when it told John F. Kennedy that its plan to invade Cuba at the Bay of Pigs “could not fail,” and it misread Soviet intentions before the 1962 Cuban Missile Crisis. Kennedy managed to avoid a nuclear war only by instigating direct communication with Nikita Khrushchev.

American intelligence wildly exaggerated Soviet defense capabilities in the 1980s, leading the U.S. to spend billions of dollars for no reason. President Reagan’s military buildup didn’t bring the Soviets to their knees; the Soviet Union collapsed of its own weight.

By all means, let’s have better intelligence. But let’s not fool ourselves into thinking that better intelligence is a substitute for better policy. This is especially true when the threat comes in the form of terrorism.

Terrorism is a tactic. It is not itself our enemy. There is no finite number of terrorists in the world. At any given time, their number depends on how many people are driven by anger and hate to join their ranks. Hence, “smoking out,” imprisoning or killing terrorists, based on information supplied by our intelligence agencies, cannot be the prime means of preventing future terrorist attacks against us. It is more important to deal with the anger and hate. This means, among other things, restarting the Middle East peace process rather than, as President Bush has done, run away from it. It requires shoring up the economies of the Middle East, now suffering from dwindling direct investment from abroad because of the violence and uncertainty in the region. And it means strengthening the legitimacy of moderate Muslim leaders, instead of encouraging extremism – as the current administration’s policies have undoubtedly done.

Equally fatuous is the notion that “preemptive war,” based on what our intelligence agencies say a potential foreign adversary is likely to do to us, will offer us protection. Terrorists aren’t dependent on a few rogue nations. They recruit and train in unstable parts of the world and can move their bases and camps easily, wherever governments are weak.

The United States cannot control or police the world. Instead, we will have to depend on strong treaties and determined alliances to prevent illegal distribution of thousands of nuclear weapons already in existence in Russia, Pakistan, India and other nuclear powers, and of biological or chemical weapons capable of mass destruction. The administration’s “go-it-alone” diplomacy takes us in precisely the wrong direction. That the United States suffers from a failure of intelligence is indisputable. The calamitous state of our spy agencies is only one part of that failure.

Robert B. Reich, a professor at Brandeis University , is the author most recently of “Reason” (2004, Alfred A. Knopf). He was secretary of Labor in the Clinton administration. This is adapted from his article in the August issue of the American Prospect, of which he is a cofounder and national editor.

Originally published in the Los Angeles Times.