The fall of Ramadi to Isis underlines the catastrophic failure of US policy in Iraq and the entire region

Forget the Pentagon’s assertion that the fall of Ramadi, barely 70 miles from Baghdad and capital of Anbar province, the country’s Sunni heartland, was a mere blip in the course of the war against Isis. The operation was the militant Islamic group’s biggest victory in a year and has dispelled the notion, fondly put about by some, that Isis is on the run. It has also dispelled any illusion that the official Iraqi army is a fighting force capable of defending its country. What victories have been achieved against Isis have been mainly thanks to Shia militias, backed by Iran, and the Kurdish Peshmerga. The recapture of Mosul, the largest Iraqi city held by Isis, looks further away than ever.

President Barack Obama says his goal is to “degrade and ultimately destroy” the self-styled caliphate. If anything, the caliphate appears to have had a significant military upgrade, judging from reports of the quantity of US-made equipment captured from the fleeing Iraqi government forces. Not least, this setback has weakened the position of Haider al-Abadi, the more inclusive Prime Minister who was strongly backed by Washington after the divisive pro-Shia and pro-Iranian policies of his predecessor, Nouri al-Maliki.

Eight years ago, as the war after the US invasion of 2003 was winding down, Anbar played a vital part in stabilising Iraq, as its Sunni tribal leaders turned on the militants. George W Bush’s troop surge consolidated that process. Thereafter, however, Mr Maliki’s policies steadily alienated the Sunni sheikhs from the Shia-run government in Baghdad.

Now those same Shia militias who last month led the recapture of Tikrit, Saddam Hussein’s old stronghold, are regathering near Ramadi in preparation for a similar, but perhaps even bloodier, assault. They will work with official Iraqi troops and in co-ordination, it is to be presumed, with increased US air strikes. But it is anything but clear whether the militias will ultimately answer to Baghdad or Tehran. Either way though, Washington will find itself once again in tacit alliance against a common foe with its long-time strategic adversary Iran.

And even success may backfire. A Shia victory in Ramadi may simply widen Iraq’s sectarian divisions. Iran’s already considerable influence over Iraqi affairs would be seen to grow, and thus perhaps intensify the Sunni resentment that largely enabled Isis’s takeover of Anbar province in the first place.

All of which poses a hideously complex dilemma for the US. It risks seeing the country where it fought a long and deeply unpopular war sliding completely into the orbit of Iran (with whom, lest it be forgotten, Washington is simultaneously trying to nail down a historic nuclear deal). Meanwhile, Mr Obama’s refusal to help anti-Assad rebels in Syria, and his perceived failure to roll back the influence of Iran in Iraq, has soured relations with the US’s traditional Sunni allies, notably Saudi Arabia and Egypt.

Inevitably, the pressure on the President to step in more decisively is growing. Yet the last thing most Americans want is for the US to become involved in another full-scale war in the Middle East. For proof, consider the 2016 Republican presidential candidates – almost all favouring a more assertive US policy overseas – who now queue up to say how they would have opposed the 2003 invasion, had they known the facts about Saddam’s non-existent WMD.

However, the arguments for increased American involvement in this new Iraq war are hard to resist. Should Mr Obama have kept US forces in Iraq after 2011? With the benefit of hindsight, the answer is surely yes. But there are ways to reverse course short of a land war: more air strikes and special operations and stepped-up cyber warfare. A melancholy phrase echoes down the years. “If you break it, you own it,” Colin Powell, then Secretary of State, warned President Bush before the 2003 invasion. Iraq was duly broken, and remains broken. In a moral sense, the US still owns it.