MOSCOW — For months now, Western policy makers have been racking their brains to figure out what strategic interests have made Russia so intent on supporting the Syrian president, Bashar al-Assad — a leader who, facing a popular uprising, seemed to be on his way out anyway.

It is an understandable question, but perhaps the wrong one. Decisions are flowing from President Vladimir V. Putin, whose career has left him overwhelmingly wary both of revolutions and of Western intervention.

This is a man who, during the death throes of the Communist system, personally defended the K.G.B.’s headquarters in Dresden against an angry crowd of Germans. And Mr. Putin’s already suspicious view of street politics only deepened with the “colored revolutions” of the mid-2000s, in which pro-Western protests, some supported by the United States, ousted a series of Moscow-friendly leaders.

Since the recent Arab uprisings began, Russian leaders have viewed them through this lens — as a product not of social change but of interference by the West, intended in part to damage Russia.