Like most wars, NATO’s five-week-old campaign to overthrow Libya’s Moammar Gadhafi has turned out to be harder than it looked.

The leaders of Britain, France and the United States, who launched the intervention, initially hoped Gadhafi’s regime would collapse quickly ― toppled either by popular uprisings or, more likely, by dissident generals.

But that hasn’t happened, at least not yet.

Instead, Gadhafi’s army has mounted a coherent counteroffensive against the country’s ragtag rebels, pushing them out of central Libya and advancing into the center of Misurata, the last major rebel-held city in the west. Given that grim situation, the “stalemate” Mullen forecast would be an improvement. And so, last week, the United States and its allies responded with a modest military escalation on three fronts.

The United States announced that it was sending missile-equipped Predator drones to help stave off a rebel defeat in Misurata, a step back into a combat role despite President Obama’s statements that U.S. forces would let others shoulder the fighting. Britain, France and Italy announced that they were sending military advisors to the rebel capital of Benghazi to help the opposition get organized. And NATO stepped up its aerial bombing of military facilities in Surt and Aziziya, two cities far from the war’s front lines, to remind Libyan officers that they won’t be safe anywhere in the country until the war ends.

To some critics, this looked like “mission creep,” the problem that arises when a limited humanitarian intervention expands to become a more ambitious war. But that’s not quite right.

Now, NATO is facing a prospect even worse than mission creep: mission failure. To prevent it, NATO has adopted a strategy that won a bad name almost half a century ago in Vietnam: graduated escalation, the attempt to find the enemy’s breaking point with the minimum necessary force.

The NATO leaders’ hope is that their still-limited military action can provoke someone in Tripoli to overthrow Gadhafi. The regime is brittle, they say; its “brother leader” is no indomitable giant like Vietnam’s Ho Chi Minh. Libya watchers in the intelligence community say every week brings new reports of generals and other Gadhafi loyalists who are on the verge of defecting.

Except most of them haven’t. And so, in addition to the best-case scenario of a palace coup, U.S. officials now talk increasingly of a longer-term scenario: a war of attrition.

In this scenario, Gadhafi’s regime gradually erodes as the army runs out of hardware and the leader runs out of money to pay his soldiers, African mercenaries and other supporters. Over time, officials suggest, the rebels will get better organized, the regime will become less capable and the balance of power will shift.

The problem is that economic sanctions are slow to bite; some countries, like Turkey, haven’t even frozen Gadhafi’s assets yet. And Gadhafi’s army doesn’t appear to need sophisticated weapons to fight the rebels.

The good news is that the rebels are getting better organized. “They have an organization chart now,” one official told me last week. Qatar and the United Arab Emirates are sending them money, weapons and ammunition, relieving the Western powers of one burden.

But military officers say turning the rebels into a fighting force with even rudimentary skills would take six months or more ― and far more trainers than the 30 advisers Britain, France and Italy are dispatching.

“This is likely to take a while,” Defense Secretary Robert M. Gates said laconically at his news conference Thursday.

If time is not on Gadhafi’s side, it won’t always be on the side of Obama, Cameron and Sarkozy either.

Their publics are already unhappy about the cost of another military commitment. NATO’s stature won’t be enhanced by a stalemate at the hands of one of the Arab world’s least impressive armies. The war has caused friction inside the alliance as Europeans pressed for more U.S. involvement and the Obama administration sought less. But having committed themselves to overthrowing Gadhafi, Obama, Cameron and Sarkozy can’t back off now.

Obama and Gates have been firm in rejecting American ground troops in Libya; this time, that’s a question for Cameron, Sarkozy and other Europeans. Before this war reaches its 78-day mark in early June, they will almost surely need to escalate it further, both to bring Libya’s agony to an end and to avoid adding their own jobs to the casualty lists.

By Doyle McManus

Doyle McManus is a columnist for the Los Angeles Times. ― Ed.

(Los Angeles Times)

(McClatchy-Tribune Information Services)