HONESTY is sometimes in short supply when accounting for military action. The appearance of Tony Blair in the debate about the latest violence in Iraq reawakened the attack dogs that have been relatively drowsy since his resignation as Prime Minister seven years ago. But also some supporters: generous observers - there are a few - acknowledge that reasons existed that justified miliary action against Saddam Hussein, even if Weapons of Mass Destruction were a fiction. Leaving him in power would not have guaranteed peace in the region.

When considering the significance of the ISIS annexation of northern Iraq, however, the Afghan war is more instructive. In response to the 9/11 attacks on the World Trade Center, President George W. Bush launched Operation Enduring Freedom against the Taliban on 7 October 2001. In his justification for the action, the President spoke of the threat that the Taliban regime posed to the West. The action was part of the US campaign against terrorism: "Today we focus on Afghanistan, but the battle is broader. . . In this conflict, there is no neutral ground. If any government sponsors the outlaws and killers of innocents, they have become outlaws and murderers, themselves. And they will take that lonely path at their own peril."

The ISIS forces currently sweeping through Iraq pose a potentially greater threat than did the al-Qaeda camps in Afghanistan. ISIS is well funded, has cut its teeth in the Syrian conflict, and contains nationals of many countries, including, in all probability, Britain. Yet the tiniest of hints at military intervention, even by former politicians, have met fierce opposition. As a conseqence, the division of Iraq into three ethnic portions - the Sunni, the Shia, and the Kurds - is rapidly becoming the accepted outcome for the country, fatally weakened by the Coalition Provisional Authority, which, under Paul Bremer, governed Iraq in the aftermath of the war. Such a division is hardly likely to be stable, however, if at least one of the parties is as trigger-happy as ISIS is proving to be. The present Prime Minister, David Cameron, on Tuesday described the rise of ISIS as "the most serious threat to Britain's security that there is today".

There is a significant shift in rhetoric, however. Mr Cameron talked of focusing "our security, our policing, our intelligence efforts" on the region, and specifically on any traffic of extremists between the UK and Iraq or Syria. Just as the Rwandan genocide taught Mr Blair the reasons for intervention, so the expensive, inconclusive actions in Afghanistan and Iraq have tipped his successors in the US and UK governments the other way. Yet the West's response to the development of a new, brutal regime in the Middle East cannot be confined to the policing of a few rogue citizens at home. Past involvement, future threats, and present atrocities all demand the world's attention. It would be a tragedy if Western governments used the bruising they received in Afghanistan and Iraq as a reason to turn their backs on the suffering people of Iraq and Syria.