Humanitarian military interventions such as the one under way in Libya typically face just two main obstacles. The first is, they're humanitarian. The second is, they're military interventions.
Humanitarianism means never having to say you're sorry. The wars it generates present themselves as peace by other means. Not politics by other means - Clausewitz's famous definition of war - because humanitarianism is, by definition, non-political. It aims for goals on which "the international community" can agree, and there's no political goal on which that illusory body can agree. It can only agree on non-controversial aims, such as saving innocents from suffering. Brandishing these, it huffily denies that its ends are political ones. Heaven forbid we should be blowing up all those things in Libya for the sake of effecting regime change.
Regime change is controversial, you see, even when the regime is that of a mad dog like Moammar Gadhafi. So for the sake of consensus - humanitarianism loves consensus, since it's just this consensus that vouches for it as non-political - intervention couches itself in neutral terms. Yes, Colonel Gadhafi must go (Barack Obama has said so), but it's not the intervention's aim to remove him. That aim is merely to stop him from doing such terrible things.
That goal is a worthy one. But it can't be achieved except by removing Col. Gadhafi. Leave a despot in power and you leave him with the power to oppress. And removing him may require more than your typical humanitarian intervention - a war fought at 15,000 feet, or with cruise missiles lobbed from distant warships, without too much danger to the intervenors. No despot has ever been deposed from 15,000 feet.
Because humanitarian intervention is War Lite, it often fails to evoke the resolve that "real" wars do. Yet, because it, too, is war, it, too, requires that resolve. Here, the historical record is clear: To be even partly successful, interventions must feature one determined power, militarily capable and clearly committed, on whom everyone else involved depends to do the heavy lifting. Examples are the U.S. interventions in Bosnia and Kosovo, the Australian one in East Timor and the British one in Sierra Leone. International endorsement merely provided the fig leaf of non-politicality.
Then there were the genuinely multilateral and, therefore, ineffectual interventions: Somalia, Rwanda, the toxic combination of the Europeans and the United Nations in the Balkans. True multilateralism features everyone hoping that someone else will do something. It means being more concerned with being seen to act on CNN than with actually accomplishing anything.
No one has strong enough reasons of their own for intervening in Libya. The strategic interests of each participant lies elsewhere (although the Europeans worry, as they did in the Balkans, about a flood of unwanted immigrants). Each country is primarily concerned with exposing itself as little as possible to danger or costs of any magnitude. Mr. Obama, David Cameron and Nicolas Sarkozy are not in strong enough positions at home to weather significant setbacks abroad. The Americans insist that the Europeans will take the lead, as both parties indulge the wishful thinking that the Arabs will. No one will admit to being in charge, nor is there avowed agreement on the goal. Yet, these are the two things that a military campaign needs above all. Mr. Obama needs to see that a president shouldn't stake his political futures on vacillating allies to whom he's offered the example of his own irresoluteness.
The half-heartedness of the intervenors against the manic determination of Col. Gadhafi; the ragtag rebels against his better-armed and -trained pretorians; our concession of control of the ground to him for unwillingness to put any of our boots there - it all seems to bode something less than a glorious victory. No war is a bargain except for those who can afford it, but cheap, half-hearted ones aren't bargains for anyone.
Clifford Orwin is a professor of political science at the University of Toronto and a distinguished fellow at Stanford University's Hoover Institution.