One must have sympathy for what President Obama is up against in Libya. He has been under attack from the left for initiating the war (that, despite the administration’s tortured terminology, is what it is by the way) without Congressional authorization, and from the right for not waging it hard enough.

To be sure, the President was in a tough spot once Qaddafi unleashed his military, militias, and mercenaries against the uprising that sought to topple him. A ruthless dictator had publicly declared that he’d show “no mercy” toward his opponents. A very knowledgeable European expert on the Arab world whom I know, a man of the left, is absolutely convinced that Qaddafi would in fact have caused rivers of blood to flow had he been left to his own devices. So Obama couldn’t very well sit back and watch the horror unfold, though when the anti-Qaddafi revolt began he was anything but eager to enter the fray.

So Qaddafi’s viciousness tipped the scales toward the interventionists in the administration and Mr. Obama, alas, found himself implicated in the Libyan conflict—and now there’s no easy way out because Qaddafi, it turns out, is not presiding over a house of cards. He may yet be forced out, but he’s not making things easy for the President, who was counting on a quick engagement.

While some empathy is in order, we don’t elect our presidents to pity them but to see them act decisively and with foresight, whether they chose to get involved in a conflict or to stay out—in other words, we want to admire them.

But that’s becoming hard even for the President’s supporters, to say nothing of those bent on using the Libyan war as an opportunity to savage him.

The President said in his recent television address that he acted to avert a “humanitarian catastrophe.” That unnecessary hyperbole has now created a big problem for the White House because the forces fighting Qaddafi, having initially gained ground in their move west, then began a chaotic retreat eastward, with Qaddafi’s forces in hot pursuit. If the President was truly forced to use American military power to prevent mass atrocities, the question that now arises is why he is not ratcheting up the pressure on Qaddafi given that the rebels are on the run. Surely, Mr. Obama must assume that bad things will happens if Qaddafi prevails. The anti-Qaddafi camp is starting to mutter that NATO, which began this campaign to protect civilians, is now letting them down.

It’s plain that what’s been done so far—the no-fly zone, air and missile attacks against Qaddafi’s forces, and an arms embargo—is not enough and that the merciless strongman is surviving.

Yet the White House has ruled out sending ground troops (for sound reasons) and has now said that the United States will not even arm the anti-Qaddafi fighters. Yet, like it or not, the United States (along with Britain and France) is enmeshed in a civil war.

What happens if the fortunes of the rebels continue to fade? Plan A, supposedly undertaken to prevent massive carnage in Libya, is not working. But there appears to be no Plan B. That’s because the President, along with Defense Secretary Robert Gates, was leery of getting involved in the Libyan conflict to begin with, but was forced to because interventionists within the administration pointed to the terrible things that would happen if Qaddafi was allowed to have his way, while neoconservatives and liberal internationalists outside the administration called for immediate action. The President hoped for a brief military engagement, but he has fallen victim to what Clausewitz called friction: unforeseen developments that shred the hopes and plans of those who enter wars. But that’s the sort of thing you’re supposed to anticipate.

No matter how you cut it, then, the President has reached what’s called a decision point: what’s been done is not doing what it was supposed to and so something different has to be tried.

But what exactly? Here’s where Mr. Obama faces another problem. He has assured the American public that this operation would last “days, not weeks” and that the United States would soon diminish its role. Yet the situation on the battlefield and his claim that America had to step in to stop a bloodbath hardly make it possible for the United States to do that, particularly because it’s not apparent that America’s NATO allies have much of a Plan B, or are likely to come up with one if the United States pulls back.

The one thing that could save the day for Mr. Obama is the unraveling of the Libyan regime—a dénouement that can’t be ruled now that Qaddafi’s Foreign Minister and onetime hatchet man and spymaster, the improbably named Moussa Koussa, defected and turned up in London. Other Libyan political bigwigs may follow in his wake, and the decision to unfreeze Koussa’s assets is a transparent and deplorable (when Pan Am 103 was blown up over Lockerbie, Scotland, in 1988 by Qaddafi’s operatives, Koussa worked for the Libyan intelligence agency, a much-feared outfit he would later head from 1994-2009, before becoming Foreign Minister) move to entice additional defectors. The problem is that success on that front is not unrelated to the ability to reverse Qaddafi’s gains on the ground. Which brings us back to the President’s decision point: it’s hard to see how the trends on the battlefield can be changed without escalating the war—something Mr. Obama has said he won’t do. That’s the bind he’s in. And he’d best not look to our NATO allies to take the steps that will get him out of it.

The sad truth is that this war is looking amateurish, however noble the motives of those who decided to wage it. The rebels are militarily weak and politically divided, and it’s not altogether evident what they stand for. Nor is it clear how much support they have—and that will be even less clear if the United States, Britain, and France (they’re doing the heavy lifting, despite the talk of NATO and the participation of aircraft from Qatar and the United Arab Emirates) become the midwives of what is supposedly a popular movement.

The quest for self-determination is often hazardous and inherently uncertain, but, as John Stuart Mill observed in his 1859 essay “A Few Words on Non Intervention” to be genuine it must be won from within, not corrupted by being enabled or accelerated from without. But acceleration is what we’re engaged in, and without much consistency considering popular uprisings in Bahrain and Qatar. There we want stability; here we want regime change. And that is what the Libyan war is about, no matter the disclaimers from the White House.