Tony Benn was brave enough in a televised debate the other night to stand up and argue that there is little moral difference between our armies killing people and terrorist ones doing the same. There was a barrage of complaint from the audience. “How can anyone say such a thing about our boys in uniform?” was its tone. The less hysterical position was about intention: that “our soldiers” don't intend to be killing people and sometimes put themselves at risk to protect civilians.

It's a thin argument that. As if to say to all the many people whose lives have been destroyed by so called legitimate armies that the intention was good. As if that is sufficient for moral cleansing. It's a naive position to take. I imagine Hitler, Stalin and Pol Pot thought their intentions were good.

None came back in Benn's defence. Had they done so they could have said that although intention is a mitigating factor, it is only a nuance. It doesn't matter so much who kills your father or your son, or why, when the end is the same. It is arrogant to absolve yourself of genocide on the basis of intention or because you can hide behind the certitude of a powerful and professional army. This is why I think Blair's justification for the invasion of Iraq was an insult to intelligence - and probably a crime against humanity. Hundreds of thousands of lives were lost as a consequence for questionable ends. The number of further lives blighted by loss and disruption is incalculable. To justify by saying “I believed I was doing the right thing” is almost puerile.

Sure there is a difference between feeling regret and feeling triumph. It is an important difference but it is a slender one and I suspect many soldiers don't feel much regret in any case. They were “just doing their job” after all. Many of the men who dropped bombs on Japan and Germany in 1945 felt no regret. There will be no shortage of military men who get a rush from the kill.

So yes, intent does make a difference but it is of little consequence. It was an insult to Tony Benn to have him heckled as he was in that hall. He's an old man now, but he's a grand old man. He did well enough defending himself but I wish there had been someone else onside to weigh in and help.