Peter Jennings says 'pretending that America can sit out (the Iraq) fight is just not realistic'. That's exactly what many pundits were saying a year ago about air strikes against Syria.

But to his everlasting credit, President Obama reconsidered, and where are we now? Syria remains a tragedy that could not have been fixed by US air power anyway. But Israel remains secure, oil is still flowing from the Persian Gulf, and there is now one less WMD-armed regime in the world. True, the terrorist threat is surely more acute, given the potential for Iraq and Syria to act as incubators for the next generation of violent fanatics. But after the experience of Iraq and Afghanistan, the bar for demonstrating that US military intervention can reduce the terrorist threat is high. As I said in my debate with Anthony Bubalo, we have a pretty good idea in this part of the world about the most effective mix of policies for combating terrorism, and military action is rarely part of that mix.

Peter says 'The opportunity for early American air strikes against ISIS has been lost', but that Obama has only delayed the inevitable because 'America's interests in the Middle East balance of power are so substantial that not even Barack Obama can ignore them forever'. I'd like to hear more about exactly what those interests are, but even assuming they are vital, it's still not clear that military action is the best way of protecting them. In fact, it will probably just damage them. America is less secure and prosperous today because of the wars in Iraq and Afghanistan (and Libya), and it is less respected in the Middle East. That's a dreadful legacy, and ought to be a caution for those demanding still more intervention.

I must correct Peter on one final point: I'm not at all motivated in this debate by a 'distaste of George W Bush'. It's more like self-loathing for my eagerness to buy the disastrous policy Bush, Cheney and Powell were selling at the time. But as President Bush himself once almost said, fool me once, shame on you. Fool me twice, shame on me.