Reacting to partial intelligence is like diagnosing cancer without testing

Military intelligence has faced this dilemma since the risks of war were first contemplated. Like the doctors, military advisers have had to assess the military strength of the enemy on the basis of limited information. The more different the culture, the more difficult it is to interpret the information.

Furthermore, the adversary is likely to send false signals. Sometimes they may want to persuade you of their weakness, to prepare the ground for a surprise attack. In recent times, potential enemies have tended to overstate their strength in order to deter attack. During the Cold War, the Soviets persuaded the West that their nuclear weapons and delivery systems were much more potent than they really were. The American Military had every reason to accept these exaggerated, or “sexed-up”, claims.

When the Cold War ended, we learned that the Soviet military “might” was more of a “mighty mouse”. Yet this “false positive” had helped to keep the peace, and finally brought down the Soviet Empire because the Americans kept upping the ante – and the costs of the conflict.

Conversely, military advisers who underestimate the strength of the enemy are normally pilloried by historians, who enjoy the benefit of 20/20 hindsight. We heap scorn on military advisers who refused to believe that Hitler’s panzer (armoured vehicle) divisions could cross Europe in a matter of days. Fortunately, the Germans in turn underestimated the strength of the British Air defences – and the power of radar in particular.

Now imagine you have been asked to advise the Bush and Blair Governments, post September 11, whether to invade Iraq.

You are peering into Iraq through a glass darkly.

You know for certain that Saddam’s regime has had a nuclear weapons program in the recent past, and used biological weapons to attack thousands of Kurds. However, you get conflicting signals about his access to weapons of mass destruction and have limited means of establishing the reliability of your sources.

A false positive (you conclude he has such weapons but it turns out that he hasn’t) means that a ruthless dictator is overturned, but the leaders of the Coalition of the Willing are pilloried by their political opponents, the Europeans, and Kim Hill. These risks are scary enough, but a false negative means that you may wake up to a phone call from Blair or Bush telling you that ten million New Yorkers and five million Londoners are now dead or dying, and you get pilloried by everyone with 20/20 hindsight, the Europeans, and Kim Hill.

And Saddam Hussein rules for a few more hours.

I suggest that in this case too, your advice would be the same as you gave your doctor – please invade, so that we know for certain. Quite simply, the risks of the false negative are far too great.

But unlike your doctors, neither Bush nor Blair will get any thanks for setting our minds at rest.

If I were in their shoes, I would now be pursuing two distinct but related lines of inquiry. First, was the quality of intelligence the best it could have been, and how might it be better next time? Second, did advisers give the right advice given the circumstances prevailing at the time?

The tragic reality of life is that the poorer the diagnostic quality of our medical tests, the greater the need to operate, and similarly, the poorer the quality of military intelligence, the greater the need to invade.

So what do we do about that?