Three times before last week's decision to launch airstrikes against the self-styled caliphate, the Islamic State in Iraq and Syria, President Obama was urged to intervene in Middle Eastern conflicts: in Libya in the spring of 2011, in Syria from 2011 onward and in Iraq two short months ago, when Baghdad was threatened by the swift advance of ISIS.
In each case, there were good reasons to hesitate. In Libya, we had little to gain strategically from Muammar Gaddafi's fall, and more to fear from the vacuum that might follow.
Syria was a more significant theatre, and Bashar Al Assad's downfall a consummation more devoutly to be wished — but there as in Libya, there was little clarity about what forces the US would be empowering and what would follow Assad's rule.
A similar problem existed for the recent battles outside Baghdad. There was no question that America had an interest in seeing the southward advance of Isis rolled back. But dropping bombs on behalf of Nuri Al Maliki's thuggish, failing government was a possible fool's errand.
All three situations were hard calls, and the fact that intervention in Libya and inaction in Syria produced similar outcomes — rippling chaos and extremists' gains — has allowed both hawks and doves to claim vindication.
But in all three debates, the noninterventionist position ultimately had the better of the argument.
We the Americans were better off sending advisers but not warplanes when Isis threatened Baghdad; we were wise not to funnel arms (or at least not that many, depending on what the CIA's been doing) into Syria's chaos; and Obama would have been wise to heed the cautious Robert Gates on Libya, rather than Samantha Power and Bernard-Henri Lévy.
The latest crisis, however, is different. This time, the case for war is much stronger, and the decision to intervene is almost certainly the right call.
In the earlier debates, the humanitarian case for action was in clear tension with strategic issues on the ground. In northern Iraq right now, the two are much more closely aligned.
Alongside a stronger moral obligation to act than we had in Syria or Libya, we have a clear enough military objective, a more tested ally in the Kurds and a plausible long-term strategy that could follow from intervening now.
The stronger moral obligation flows from two realities. First, this humanitarian crisis is one our actions directly helped create: The cleansing of Christians, Yezidis and other religious minorities began in the chaos following our invasion of Iraq, and it has taken a more ruthless turn because Isis profited from the fallout from our too-swift 2011 withdrawal.
Second, Isis represents a more distinctive form of evil. As the blogger Razib Khan argued last week, the would-be caliphate is "utopian in its fundamentals," and so its ruthless religious cleansing isn't just a tyrant's "tool to instil terror" and consolidate power; it's the point of gaining power, an end unto itself.
These arguments — a distinctive obligation, a distinctive evil — still do not compel action absent a clear strategic plan, which is why the president was right to hesitate to take the fight to Isis around Baghdad.
But in this case, such a plan is visible. We do not need to re-invade or re-stabilise Iraq to deal Isis a blow and help its victims, because Kurdistan is already relatively stable, and the line of conflict is relatively clear.
And the Kurds themselves, crucially, are a known quantity with a longstanding relationship to the United States — something that wasn't on offer in Libya or Syria.
So the US intervention in northern Iraq has a limited, attainable objective: Push Isis back, allow its victims to seek refuge in Kurdish territory and increase the Kurds' capacity to go on offense against the caliphate.
But if this president is thinking strategically, instead of just conducting a humanitarian drive-by, this intervention could also set the stage for a broader policy shift.
Swiftly or gradually, depending on political developments in Baghdad, an independent, secure, well-armed Kurdistan could replace an unstable, perpetually fragmenting Iraq as the intended locus of American influence in the region.
That influence will be necessarily limited. There is not going to be a major American-aligned model nation in the Arab world anytime soon, of the sort the Iraq invasion's architects naïvely hoped to build.
But by protecting a Kurdistan that can extend protection to groups made homeless by the fighting, the US can still help save something from the wreckage. Not a model, but a refuge.
- The New York Times News Service