For the 20 years between 1991 and 2011 - the interval between Operation Desert Storm and the final withdrawal of U.S. forces after a lengthy occupation of Iraq - Washington policymakers, Republican and Democratic, relied on various forms of coercion to align Iraq with American expectations of how a country ought to run.

The effort failed abysmally.

Now here is Barack Obama, elected president in 2008 largely because he promised to end the Iraq war, back for another bite at the apple.

A small bite - since Obama's aversion to large-scale intervention on the ground will largely restrict the US effort to aerial bombardment supplemented with a bit of advice and equipment.

Whether the president will make good his promise to "degrade and ultimately defeat" Islamic State militants will depend less on the accuracy of US bombs and missiles than on the effectiveness and motivation of surrogate forces fighting on the ground. Identifying willing and able proxies is like to pose a challenge.

The Iraqi security forces, created by the US at such great cost, have shown neither fight nor skill. Though the Kurdish peshmerga have a better reputation, their primary mission is to defend Kurdistan, not to purge Iraq as a whole of invaders. The Syrian army is otherwise occupied and politically toxic.

The countries that ought to care more than the US simply because they are more immediately threatened by Islamic State fighters - Iran, Turkey, Egypt and even Saudi Arabia - have not demonstrated a commensurate willingness to act.

The best hope of success may lie in the possibility that Islamic State militants will overplay their hand - their vile and vicious tactics alienating erstwhile collaborators and allies, much as the behavior of al Qaeda in Iraq alienated Sunni warlords during the famous US surge of 2007-2008.

This much is certain, however: Even if Obama cobbles together a plan to destroy the Islamic State, the problems bedeviling the Persian Gulf and the greater Middle East more broadly won't be going away anytime soon.

Destroying what Obama calls the Islamic State of Iraq and the Levant won't create an effective and legitimate Iraqi state. It won't restore the possibility of a democratic Egypt. It won't pull Libya back from the brink of anarchy.

It won't end the Syrian civil war. It won't bring peace and harmony to Somalia and Yemen. It won't persuade the Taliban to lay down their arms in Afghanistan. It won't end the perpetual crisis of Pakistan. It certainly won't resolve the Israeli-Palestinian conflict.

All the military power in the world won't solve those problems. Obama knows that. Yet he is allowing himself to be drawn back into the very war that he once correctly denounced as stupid and unnecessary - mostly because he and his advisers don't know what else to do. Bombing has become his administration's default option.

Rudderless and without a compass, the American ship of state continues to drift, guns blazing.-Reuters

(Andrew J. Bacevich is author of "Breach of Trust: How Americans Failed Their Soldiers and Their Country," just out in paperback. His MOOC on America's "War for the Greater Middle East" goes live later in late September. The opinions expressed are his own.)