As President Obama sets out to reshape US foreign policy, he and his advisers will have an urgent need for good intelligence. Without it, policy is all too easily shaped by fear, ignorance or - just as bad - optimism. In discussing with his spymasters how to get the best out of the intelligence community, the president would do well to keep in mind crucial lessons from the cold war era, starting with the importance of getting inside the minds of adversaries. "One of the things that kept the cold war scary," secretary of defence Robert Gates recalled in 2006, "was the lack of understanding on each side of the mentality of the other."
The guru on the subject, Andy Marshall, who has headed the Pentagon's secretive Office of Net Assessment for the past 35 years, puts it this way: "Valuable insights can, of course, be gained by closely observing what the other side does, but the real gains come from asking why they have done it. It may not seem reasonable to you, but it probably does to him. Rationality, after all, can come in many different forms."
The military threats America faces now are fundamentally different. But the task of "getting inside the mind" should remain a guiding principle. Nowhere more so than in the case of Iran, whose place on the list of diplomatic priorities was confirmed by last week's IAEA report that Iran has enriched enough uranium to build a nuclear weapon.
Washington should endeavour to understand what lies behind various Iranian actions, but in doing so remember that regardless of how good the intelligence from technical sources and documents might be, and never lose sight of the special quality of intelligence that only people provide. Good agents are better than documents at explaining how leaders think. And they can expose weaknesses that can be exploited.
Some of these are closely related to deterrence. "What saved us," James Schlesinger, who served briefly as director of central intelligence in 1973, told me, "was the determination with which we developed and exploited new intelligence technology." Analysis of the results enabled the US to work towards ensuring that Soviet leaders would never think that they might be able to prevail, let alone "win", a nuclear war.
To deter a nuclear-armed Iran Washington will have to know much more about the fears of the mullahs - and their military supporters. Even more worrying is the spectre that within five years terrorists could be using biological or nuclear weapons. To find out what these groups are up to and guard against attack, the US needs to continue investing in new intelligence technology.
History reveals the potential of intelligence - just as it underlines the importance of fundamental questions: what is happening? Is it new? Why are they doing it? What are the implications? Had analysts posed such questions they might have realised Saddam Hussein had little in the way of weapons of mass destruction - but he wanted his people and his enemies to believe he had a lot.
There is another lesson the US will ignore at its peril - the need to grasp an adversary's culture. After Khrushchev shattered American self-confidence by putting Sputnik into space, Congress swiftly approved the National Defense Education Act. Soon many young Americans were studying Soviet affairs. They learned to look at what was really happening, rather than accept preconceived notions, especially the one about the Soviets being unfathomable. Now there is an equally urgent need for young Americans to comprehend the intricacies of more difficult languages and complex cultures. And young Britons and Europeans need to do the same.
Gordon Barrass, a former British diplomat and the author of The Great Cold War - A Journey Through the Hall of Mirrors.