Some might argue that the rise of separatist insurgencies the North Caucasus and elsewhere in Russia is a result of Moscow's own misguided policies, and that the fate of the Assad regime is irrelevant to that dynamic. The Kremlin, however, believes that it knows better. From the 1990s through the early 2000s, Moscow had accused Saudi Arabia and other Gulf states of supporting the separatist rebellion in Chechnya. But as Moscow's harsh military tactics subdued that insurgency, a Saudi-Russian rapprochement began in 2003.

Russia believes that as bad as Assad is (and Russian statements indicate Moscow understands that Assad is bad), what will follow him is likely to be far worse. Russian officials and analysts are adamant that Sunni Arab fighters linked to al-Qaeda will be in the strongest position to take power if Assad is overthrown, and that they will then move to establish Taliban-like rule in Syria. That scenario would imperil not only Syria itself, but also its immediate neighbors and Russia's restive North Caucasus, where predominantly Muslim ethnic groups have long chafed under Moscow's rule.

Why does Putin have Assad's back? And what will the Russian leader do if the Obama administration does launch a military strike against Syria?

Even after Iran appeared to distance itself from Damascus in response to reports that the Bashar al-Assad regime used chemical weapons on its opponents last month, Russia has remained a vociferous supporter of its Syrian ally. The Kremlin has also unflinchingly opposed President Barack Obama's call for a military strike to punish the Assad regime over to its suspected use of chemical weapons, even beefing up Russia's naval presence in the waters off Syria.

Even before the Arab uprisings began in early 2011, Riyadh-Moscow ties had begun to fray. Russia believed Saudi Arabia and Qatar were somehow responsible for renewed anti-Moscow agitation throughout the North Caucasus. And when Saudi Arabia and Qatar supported rebels seeking the downfall of long-standing Russian allies in Libya and then in Syria, the Kremlin imagined a larger, Gulf-backed plot aimed at Russia.

This Russian view of Saudi and Qatari aims, in my view, is mistaken. Neither Riyadh nor Doha wishes to see the rise of Islamist militancy, which potentially threatens their own well-being. They're more motivated by fear of Iran. Syria's minority Alawite regime has been closely allied to Tehran, and the rise of opposition to it on the part of the Sunni majority was seen in Riyadh and Doha as an opportunity to weaken Iran.

Even though many Russian specialists understand that Iran is their main concern, the Kremlin maintains its starkly negative view of Saudi and Qatari intentions. Indeed, Moscow imagines itself more at odds with these two Arab monarchies than it is with the United States over Syria.

Before the widely reported use of chemical weapons on the outskirts of Damascus last month, Moscow may even have believed it had a tacit understanding with Washington on Syria. While the Obama administration criticized the regime and even called for Assad to stand down, unlike Saudi Arabia and Qatar it has not offered much practical help to the Syrian rebellion. And since Moscow's experience will have taught the Kremlin that it is unable to prevent U.S. interventions once Washington's mind is made up, Putin may even have convinced himself that Obama really did not want to see the downfall of Assad -- thus giving Moscow a freer hand to support him.

But Obama's response to the chemical weapons reports will have disabused Putin of the idea that Washington's opposition to Assad is simply rhetorical. Moscow now fears that if President Obama carries out his threat to launch a military strike against Syria, the balance of forces there will shift in favor of the opposition and potentially bring down the Assad regime.

As much as Putin does not want this to happen, though, Moscow will not intervene in Syria to defend Assad. Russian officials, including Putin himself, have stated this repeatedly. And passivity would be consistent with how they have acted in response to other post-Cold War American military interventions, such as those in Kosovo, Afghanistan, Iraq and Libya. Moscow is no longer willing or able to get directly involved in conflicts beyond the boundaries of the former Soviet Union.

Until the Obama administration does launch a military strike on Syria, though, Putin still hopes to prevent it. But if he can't prevent it, then he hopes to limit it. And if he can't limit it to his satisfaction, then he hopes to discredit it.

And, of course, the Kremlin is not alone in seeking to do this. Most of the allies that Obama had sought to rally in favor of a strike on Syria have so far proven reluctant to support him. And Obama is facing stiff opposition domestically both in Congress and in the polls.

These other parties, of course, do not oppose Obama on Syria out of any desire to curry favor with Moscow. Nor can Moscow do much to sway the decisions of those Obama is courting to support an attack on Syria. Moscow's ability to get what it wants in Syria, then, depends on decisions made by others -- not least Obama -- over whom Putin has very little control or even influence.