Tony Blair has come in for direct criticism from archbishops and the parents of fallen soldiers, and even Labour Party supporters—the people who elected him—now appear to despise him. But is he being judged unfairly for an unfortunate outcome, rather than on the quality of his decisions?

As Prime Minister, Tony Blair ordered British troops into action on four occasions: Kosovo in 1999, Sierra Leone in 2000, Afghanistan in 2001 and Iraq in 2003. He also presided over the signing of the Good Friday agreement in 1998 that brought an end to the conflict in Northern Ireland. That’s a lot more life-and-death decision making than most statesmen get to do.

Few would argue that Tony Blair deserves praise for the Good Friday agreement. And while a decision to go to war is always controversial, most people have a positive view of the interventions in Kosovo and Sierra Leone.

The decisions that have not gone so well are in Afghanistan and Iraq. The Afghan war has lasted a lot longer than it should and there is certainly controversy today as to why we are still there. There have been many good and bad decisions made over the years, but the original decision to go in probably cannot be faulted. Amongst many considerations, the United Kingdom was responding to its NATO treaty obligation to come to the aid of an ally who had suffered an unprovoked and vicious attack. France reneged on its obligation and found itself the subject of worldwide ridicule.

That leaves Iraq, from which Tony Blair’s negative legacy seems primarily to flow. So let’s build a simple decision tree and see what insight we can draw.

Blair had the choice to take the UK to war in Iraq, or not. He had many uncertainties to consider, but topmost must have been whether Saddam Hussein had weapons of mass destruction (WMD), or not. As it turns out, no WMD have been found—we will leave to one side the fact that absence of evidence is not evidence of absence—and the outcome is probably best described by the single word “anger”. But suppose WMD had been found. I think the best description of that outcome would have been “relief”. And if we had not gone to war and Saddam did have WMD—remember, he had a track record of genocide against his own Kurdish and Shia citizens, a long, bloody and unfinished war against Iran, and Scud missile attaches aimed at Israeli population centres—the word is surely “horror”. There is one remaining possibility: we did not go to war and Saddam did not have any WMD—the word perhaps is “yawn”.

The quality of the decision to go to war ought to hinge critically on the probability that was assigned to the “Saddam has WMD?” uncertainty, at the time the decision was made. Tony Blair did not have the benefit of hindsight, only the intelligence briefings he was receiving at the time. I have only the benefit of the discussion on the BBC and in The Times, and what was published in the so-called “dodgy dossier” (which I actually read at the time). The Syrians, Saddam’s neighbours and fellow Ba’athists, certainly thought there were WMD. They voted against Saddam in the United Nations Security Council before the war. There’s even evidence that Saddam himself believed he had WMD. The consensus opinion on TradeSports’ prediction market was about 70%. This is certainly high enough that I would not have been willing to risk leaving Saddam alone to play with his toys.

There’s one final consideration. Suppose we had not gone to war. Would we really be yawning and letting the Middle East go on its way in peace and tranquillity? Somehow I doubt it. Iran will probably pull back from developing its own nuclear arsenal, once it feels it has acquired enough national prestige (see Bruce Bueno de Mesquita’s analysis on TED). But I don’t think it would do so if Saddam were still in power. And I don’t think Saddam would have taken long to reactivate his WMD programme. I think the outcome would quickly have turned from “yawn” to “cataclysm”.

Was the Iraq decision a good decision? Yes, I think so. Would I have preferred a better outcome? Most definitely. This is a case of good decision–bad outcome.

I advise my clients to judge people on their decisions, not on outcomes. Politicians deserve the same courtesy. And I would much rather have a decisive leader with the ability to commit to action, than one who cannot decide what biscuit he likes. As for President of Europe, that’s another discussion...

See also:

• Service honours UK Iraq personnel, a BBC report of the 9 October 2009 service of commemoration honouring British military and civilian personnel who served in Iraq, in which the Archbishop of Canterbury criticised policy makers for failing to consider the human and other costs of the conflict. The father of one soldier who died in Iraq refused to shake Tony Blair’s hand after the ceremony. Instead, he told the former PM: “I’m not shaking your hand, you’ve got blood on it.”
• Bruce Bueno de Mesquita makes political and foreign-policy predictions based on computer modelling and game theory. See his recent presentation at TED, or read his book, Predictioneer.