Paul Vallely: 'Good faith' isn't usually good enough

On the Iraq war, Tony Blair says he did what he thought was right. Had he listened, he would have thought differently

We pretty much know what Tony Blair is going to say at the Chilcot inquiry this week. A chess grandmaster would create a name for it – something like the Fern Britton gambit out of the Trimdon variation of the Brighton defence. Let me explain.

"I ask you to accept one thing," Mr Blair said in his resignation speech at Trimdon Labour Club in 2007. "Hand on heart, I did what I thought was right." We had already had as much of an apology as we were going to get, in his speech to the Labour Party conference in Brighton in 2004, a year after the invasion of Iraq, when he said about weapons of mass destruction, or rather the lack of them: "I can apologise for the information that turned out to be wrong, but I can't, sincerely at least, apologise for removing Saddam. The world is a better place with Saddam in prison not in power."

A little more tactical detail emerged on the former prime minister's defence in an interview with Fern Britton last month. Asked if he had known there were no weapons of mass destruction, would he still have gone on with the invasion, he replied: "I would still have thought it right to remove him... I mean, obviously you would have had to use and deploy different arguments about the nature of the threat." But he added: "I can't really think we'd be better with him and his two sons in charge."

What it all amounts to is this: I may have been wrong on the detail, but I was correct about the big picture and did what I thought was right.

There are all sorts of political resonances in this about whether international law justified regime change without weapons of mass destruction. There is fuel, too, for the claim that Mr Blair repeatedly misled MPs about the "clear and present danger" Saddam posed to Britain's national security. But it also raises interesting moral questions about the whole business of intention and the extent to which "I did what I thought was right" is an acceptable defence.

In one sense it is obviously not. We have no truck with a schizophrenic who says "I killed him because the voices told me to", though we may send him to secure hospital rather than a prison. And no one accepts that Hitler meant well because he stuck firmly by his eugenicist principles that mentally handicapped people would be better off dead. Internal consistency is not enough. Right is about more than integrity. We make judgements about the nature of those principles. And those judgements reflect the shared values of a society.

And yet it is not so simple as that. For we also respect the right of an individual to make a different judgement from the majority. In war we call that conscientious objection. In medical ethics we permit doctors to cite conscience as acceptable grounds in law for refusing to do abortions or IVF work. Even that most authoritarian of organisations, the Roman Catholic Church, recognises a well-informed conscience as the final arbiter of moral decision-making.

Conscience is the last court of appeal. "If I am utterly convinced, how else could I act? Morally speaking it would be wrong to do anything else. My judgement may be faulty but my moral sense cannot be queried." As a society we don't just accept conscience, we expect it. We reject its opposite, the Nuremberg defence of "I only did what I was ordered to do".

But we do place limits on con

science. Some Muslim student doctors are now telling their medical ethics lecturers that the right of conscience should extend to them, as Muslim men, refusing to examine the bodies of women. They have been given short shrift, but it is problematic, in logic, to say why conscience may be exercised over abortion but not over gender. (Or in the case of Catholic adoption agencies, over sexuality). In the end the answer is empirical rather than logical: that is what this society has decided.

That raises the question of what a society wants in a leader. "My duty was to put the country first," said Mr Blair at Trimdon. We like that when his view of the national interest concurs with ours. But what about when it does not? When George Bush declared that he was not signing Kyoto because climate change curbs were not in America's best interest, most outsiders bridled, yet Bush was doing what he saw as a leader's job. Rowan Williams does the same when he suppresses his personal views on homosexuality in favour of a strategy to try to keep the Anglican Communion together; he sees that his role supersedes, at present, his personal views.

But Tony Blair offers a different view. "My duty was to put the country first," he said at Trimdon, and "in time you realise that putting the country first doesn't mean doing the right thing according to the prevailing consensus or the latest snapshot of opinion. It means doing what you genuinely believe to be right. That your duty as prime minister is to act according to your conviction."

Up to a point. Most moral philosophers accept that intention is a crucial determinant of culpability. So do theorists of jurisprudence; in criminal law, mens rea (guilty mind) is usually one of the necessary elements of a crime. But last week Frances Inglis was sent to prison for the "mercy killing" of her brain-damaged son. She did it, she claimed, with love rather than malice in her heart, but the law recognised no such distinction.

There is something purist about the "I did what I thought was right" defence. Of course, there are deontological truths such as "It is wrong to lie"; but it may be right if lying to a gunman will save the life of someone hiding in the next room. Socrates drank poison, when he could have fled Athens, because a court had sentenced him to death and to obey the law was right. But we want political judgements, not dogmatic philosophy, from our prime ministers. Consequences temper principles.

When a child knocks a cup of coffee over the new sofa most parents have little truck with the teary response: "I didn't do it on purpose." Rather they reply: "We told you if you kept running round something bad would happen."

Tony Blair might argue that he had successfully used military force to oust Slobodan Milosevic in Serbia or restore democracy in Sierra Leone. But he also ought reasonably to have been able to work out that invading Iraq might produce an aftermath of more pain than gain. Plenty of people, like Robin Cook, were warning him so.

In such a situation "I did what I thought was right" is not a get-out-of-jail card, for it is his judgement not his integrity that is being questioned. John Paul II challenged that when he issued stern injunctions against the invasion of Iraq. And yet Mr Blair, even though he was about to jump the Anglican ship and go over to Rome, ignored him too.

Do you have a best friend, Fern Britton asked Tony Blair, someone you can phone and ask about decisions like this? "There isn't one in those situations I am afraid," Mr Blair replied. "I mean, there just isn't one so... it's the way it is."

The sad truth is that there were plenty. He just did not want to listen to them.

Alan Watkins is away