The US is stepping into its third Iraq war in 24 years. However, if President Barack Obama has his way, this one will be fought under different rules. In a speech at West Point last month, Obama outlined a new “light footprint” approach to fighting terrorist groups in the Muslim world, one that relies mostly on US-supported local forces, not American troops. The strategy, he explained, “expands our reach without sending forces that stretch our military thin or stir up local resentments”. The countries he had in mind, Obama said, were Yemen, Somalia, Libya, Mali and Syria. He barely even mentioned Iraq. But now, thanks to the march towards Baghdad by the Islamic State of Iraq and the Levant (Isil), Obama’s still-unfinished counter-terrorism strategy faces a real-world test sooner than anticipated. Why is Obama, a president who won the White House by promising to get the US out of Iraq, sending US troops back in?

Obama cited two principal reasons: The destabilising effect of a civil war in a region that produces much of the world’s oil, and the danger that Isil could use territory it controls as a base for terrorism against the US. But he put most of his emphasis on terrorism and not only because that is a stronger selling point for war-weary American voters. If there is an Obama Doctrine in foreign policy, it begins with one rule: No more large-scale military intervention. But the rule comes with a major exception: Terrorism. Obama withdrew US troops from Iraq, is withdrawing from Afghanistan and has repeatedly rejected proposals for using military force against the regime of President Bashar Al Assad in Syria. But he has shown no such hesitation when it comes to striking at terrorists who have a history of plotting attacks against US citizens. He presided over a massive increase in the US drone war against extremist groups in northwest Pakistan, a similar battle against extremists in Yemen and a smaller campaign in Somalia. Now he and his aides are laying the groundwork for possible US air strikes against Isil in Iraq — and, they say, in Syria as well.

If Isil establishes an extremist mini-state in the borderlands between those two countries, Obama warned last week, it could use it to target “our personnel overseas and eventually the homeland”. US officials say they are particularly concerned that hundreds of foreigners, some with US passports, have travelled to the Middle East to be trained by Isil. Even before Isil launched its offensive in Iraq, US officials had decided that air strikes against the group’s bases in Syria would be legal if the president concluded that they posed an “imminent threat” to Americans. Such attacks could also have a welcome side-effect on Syria’s civil war, some officials argue, by weakening Isil and strengthening more moderate rebels that the US has haltingly supported. Still, direct US strikes against Isil are not imminent, officials say. First, they do not appear to be necessary to protect Baghdad, since the military situation around the Iraqi capital has stabilised. Second, the US military does not have the kind of detailed intelligence it needs before launching drone strikes, especially in areas where extremists are mingled with civilians. Moreover, Isil is fighting in an alliance with some of Iraq’s less-radical Sunni factions and the administration does not want to alienate their followers by hitting them. Instead, it hopes to isolate Isil from the others. (That is another reason why strikes may be directed against Isil’s bases in the desert: Less danger of collateral damage.)

US officials do not use these words — at least not in public — but their strategy has a Plan A and a Plan B. Plan A is to encourage Iraq’s political factions to form a government more inclusive than the current one of Prime Minister Nouri Al Maliki, who has alienated Sunnis by barring them from government positions and persecuting their leaders. A broader government can become the “partner” that Obama’s counter-terrorism strategy envisions, with an Iraqi army capable of shouldering the fight on the ground. Last Friday, Obama mentioned Yemen as a potential model for Iraq: A country where the US has no combat troops, but has launched an estimated 108 air strikes since 2009 in support of a friendly government. But if Plan A fails, there is Plan B: A continuing, mostly diplomatic, effort to stave off all-out civil war in Iraq, combined with selective air strikes against Isil. Neither one is merely a short-term, emergency response to Isil’s march to the gates of Baghdad. Obama and his aides are planning a long-term effort to try to stabilise Iraq — or, failing that, at least to keep Isil from growing stronger.

Most Americans — left, right and centre — surely cringe at the thought of sending troops back into Iraq. But while Obama’s Republican critics have denounced him for past missteps, none of them has offered a good alternative for the present crisis.

Obama has promised that this time it will be different. His limited goals do not include the shining Arab democracy promised by George W. Bush, nor even the fully stabilised Iraq he had once hoped for. And US troops will not go into combat. The results are certain to be messy, even if US policy succeeds on every front (and it will not). But that is one hard-earned lesson from the last decade of US foreign policy: If you want to stay off the slippery slope to deeper intervention, make sure to keep your ambitions modest.

— Los Angeles Times