NATO secretary general Anders Fogh Rasmussen reiterated Friday that the Alliance will not intervene militarily in Syria. While he repeatedly made the same assurances regarding Libya before NATO's ultimate action, there's good reason to believe him this time.

First, as Rasmussen noted, "There is a clear difference between Libya and Syria. We took responsibility for the operation in Libya based on a very clear United Nations mandate to protect the civilian population and we got active support from countries in the region. None of these conditions are fulfilled in Syria." Both NATO and the Obama administration have consistently pointed to the need for Security Council coverage and regional backing. Neither will be forthcoming for Syria. Russia, which holds veto power, has doubled down on its support for the Assad regime. And the region is divided, with Saudi Arabia, Qatar, Turkey, and Al Qaeda siding with the rebels and Iran, Iraq and Hezbollah backing the government.

Second, and more fundamentally, with the possible exception of Turkey, no major NATO ally has a national interest in taking on this fight. The near-universal Western view at the outset of the conflict, of a popular uprising of freedom fighters ushering in an Arab Spring, has given way to a much gloomier and pessimistic outlook.

Gideon Rachman of the Financial Times quotes "one EU minister" explaining, "We thought we were dealing with democratic protests that would topple Bashar al-Assad very quickly." Two years later, he's still standing and seems to be gaining ground. Another "western minister" tells Rachman, "The Russians kept telling us we were naive, and maybe we were."="#axzz2uhbpxjjo">

Essentially, while virtually all in the West view Assad as the clear bad guy, there's not much sense of who the good guys are. The National Coalition, the only opposition entity with something like universal Western backing, is led by exiles and has zero chance to emerge as a significant player in any post-Assad government. Meanwhile, the dominant rebel factions look increasingly scary. As Atlantic Council senior advisor Harlan Ullman warns, "history suggests that the elements most hostile to the West and most compatible with Islamic extremism are likely to dominate."

All agree that the death toll—by most counts now above eighty thousand—is horrible. The problem, Ullman puts it, is "every option is bad. Some are worse."

Certainly, NATO publics are not pressuring their governments to intervene. A new Gallup survey shows 68 percent of Americans oppose any use of military force. This, despite 58 percent in the same survey believing diplomatic efforts will not resolve the conflict. A new Observer/Opinium poll of Britons found fully 78 percent opposing any intervention, with even supplying of arms to the rebels garnering only 24 percent approval. And a March Pew poll found opposition from 82 percent of Germans, 69 percent of Frenchmen, and even 65 percent of Turks.

The EU's ban on arming the rebels expired last week, not because European governments have forged a consensus on Syria policy but because they could not. While Britain and France have declared they are not yet prepared to supply arms, they argued that the ban symbolically strengthened Assad's hand. Others, led by Austria and Sweden, contend that more weapons would simply bring more violence and instability.

Meanwhile, Russia's decision last week to supply S-300 surface-to-air missiles to the regime further complicates the implementation of a no-fly zone. Not only does it significantly increase the danger of NATO planes and personnel getting shot down but, as Jane's Air-Launched Weapons editor Robert Hewson points out, efforts to take out the missiles would kill the accompanying Russian military advisers. (And, as already noted, Moscow’s move here should finally put to rest any notion that Russia will sign off on any Security Council resolutions targeted at Assad.)

Talk of implementing a no-fly zone is in any case a misnomer. When implemented in the 1990s in parts of Iraq and later in the various Yugoslav wars, they were quite simple: U.S. or NATO forces, who had unquestioned air supremacy, would simply shoot down any regime airplane or helicopter that entered into set pieces of airspace. Now, as my Atlantic Council colleague Fred Hof notes, what's being contemplated is much more complicated: "to eliminate or seriously degrade the ability of the Assad regime to conduct missile, aerial, and artillery attacks against populated areas." In other words, a pretty expansive entry as a combatant against the regime.

Former U.S. ambassador to Iraq Christopher Hill, who believes that Assad "should face prosecution for war crimes," nonetheless warns that we "ought to pause and reflect on who would rule Syria if he were toppled tomorrow."

Given the lack of viable military options or any political will to carry them out, both the Obama administration and NATO naturally insist on a "diplomatic solution." Alas, not only is it far from clear what that would look like, but the Obama administration's impetuousness at the outset of the crisis complicates it. Hill correctly notes that Obama made a critical error in August 2011 when he declared that Assad must go because, "By repudiating Mr. Assad without any nuance, the administration complicated its ability to negotiate with minority Kurds, Christians, and Druze, who are suspicious of Mr. Assad but even more fearful about the uncertainty that would accompany a takeover by Sunni-led rebels."

We would appear to be left with the dilemma that the American public seems to have unconsciously accepted in the aforementioned poll: diplomacy is unlikely to work and the costs of military intervention—which itself is unlikely to achieve our objectives—is simply too high. Which means facing up to the “unpleasant truth” that Edward Luttwak infamously pointed to in 1999: “although war is a great evil, it does have a great virtue: it can resolve political conflicts and lead to peace.”

Ullman shares the unhappy thought that, “A British member of Parliament who knows the region well says that if Assad defeats the opposition, at least 100,000 people will perish. And if Assad goes, that number could double or triple in the ensuing bloodbath.” But, as we’ve seen recently in Iraq and Afghanistan, and to a thankfully lesser extent in Libya, Western military intervention doesn’t preclude massive slaughter in ensuing sectarian violence.

There’s a reverse Pottery Barn Rule in effect here: If we didn’t break it, we don’t own it.

James Joyner is managing editor of the Atlantic Council.