Fairfax Media

By Tom Switzer

We all know that the group known as Islamic State is evil. Barbarians whose goal is to expand their power with gruesome murders and mass killings deserve to be preceded by that adjective.

But the goal of eradicating evil such as IS, if one is concerned to be successful and not merely to feel righteous, is complicated and fraught with the danger of unintended consequences.

US President Barack Obama was right to order limited air strikes to stop the jihadists from carrying out a genocide in northern Iraq. Ditto his decision to provide humanitarian relief to Yazidis and other desperate Iraqi minority groups fleeing IS's rampage.

It now appears likely Washington will broaden its campaign against IS across Iraq and perhaps extend air strikes into Syria. As someone who opposed the decision to invade Iraq in 2003, let me offer a few words of caution.

For one thing, escalation of the US military campaign could inflame sectarian tensions by reinforcing perceptions among even moderate Sunnis in Iraq and across the region that Washington is favouring the Shiite regime in Baghdad.

Most of us in the West think the US strikes against IS in northern Iraq are self-evidently justified. Many Sunnis think differently. From the British to the Baathists, they held a disproportionate share of power and resources in Iraq. Since the downfall of Saddam Hussein, however, the majority Shiites have become the political winners bent on ruthlessly discriminating against the minority Sunnis as payback for decades of mistreatment.

Many Sunnis have felt Washington has facilitated a violent Shiite offensive against themselves. When they see the US intervene against the Sunnis as soon as other ethnic groups are threatened, they assume the Americans are helping the Shiite. US escalation of the war, even in the cause of defeating Islamist terrorists, would affirm this narrative.

Another cause for scepticism: the conflict is complicated and morally ambiguous. In response to the butchery of US journalist James Foley, many people have purveyed a good-versus-evil world view.

But remember this: the Sunni extremists who want to form a terrorist state in the heart of the Persian Gulf are waging war against an authoritarian Shiite regime in Baghdad that is strongly supported by a terrorist-sponsoring Shiite power that wants to dominate the region (Iran). As Prime Minister Tony Abbott said of Syria's civil war a year ago, this is a fight between "baddies".

Now calls for a rapprochement with Syrian President Bashar al-Assad are escalating. Last weekend, the former head of the British Army Lord Dannatt called on the West to form an alliance with Damascus to beat IS.

Think about that: the US and Britain are trying to destroy the very enemy (IS) that seeks to destroy the very regime (Syria's dictatorship) that Washington and London have been trying to destroy since 2011.

Indeed, a year ago both Obama and British Prime Minister David Cameron were lobbying the Congress and the Commons, respectively, to authorise military strikes against Damascus. To this day, the stated Syrian policy of the US is "regime change".

If we accommodate Assad, the West would be applying the old diplomatic dictum "the enemy of my enemy is my friend" with excessive zeal.

There is another case for caution about escalating the conflict: Americans are in no mood to go abroad in search of new monsters to destroy. As Iraq and Afghanistan showed, Americans might be easily aroused to join the battle cry, but they lack the attention span and staying power to stay the course. Ending evil is a long, hard slog.

One suspects Obama, much to the ire of neo-conservatives and liberal hawks, recognises these realities. Sure, he knows IS represents pure evil, that its recent advances into Kurdish areas needed to be stopped, and that it has attracted terrorists from Syria and even Western nations, such as Australia. But he is also aware of the limits to US power, especially in a region that will not conform to Western expectations.

Moreover, as the distinguished Harvard professor Stephen Walt has argued, IS is a lightly armed group of thugs (with no navy and air force) whose alleged "caliphate" stretches across mostly empty flat terrain.

It can defeat small units of divided, poorly trained and demoralised troops, but not a decent military with some resolve. It clearly cannot topple Assad — certainly not without Western help.

Obama will try to give local actors such as the Kurds in the north, Baghdad in the Shiite south, Turkey, perhaps even Iran, and Syria the time to defeat or at least contain the problem themselves. It is ultimately their fight, not the United States' — unless the President makes it so.

This article was originally published in the Fairfax Media