The question is: Why are the Russians refusing to budge? What stake does Moscow have in sticking with Assad until the bitter end? Russia has no vital interests in Syria. Damascus has been a major customer for Russian arms for more than four decades but has paid only a fraction of what it owes for those weapons. As for Russia’s so-called naval base in Tartus, in fact it is little more than a refueling station with a staff of four people.

Some analysts argue that Moscow is still angry at the United States, France, and Britain for over-reaching with its U.N. security council resolution, meant to protect Libyan innocents, by using it to depose Muammar Qaddafi in October 2011. Putin, this argument goes, now fears that the United States is getting regime-change happy and may come for him next. But this doesn’t hold up: As the Russians themselves acknowledged with their 2008 invasion of Georgia , U.N. security council resolutions don’t crush governments; armies do.

Others claim that Moscow is terrified of the rise of the Islamists throughout the Middle East. It’s true that the Russians are worried about their own Islamist problem—the Chechen rebels that have often taken the war to Moscow itself. And there are reports of Chechen fighters scattered among different Syrian rebel units. But the notion that Putin is more generally worried about the rise of radical Islam is nonsense. After all, by supporting Assad, Putin has aligned himself with Iran and Hezbollah, the most dangerous radical Islamist bloc and the one that, unlike the Salafists and Muslim Brotherhood, is marching toward a nuclear weapons program.