“If you look at events over the past 20 years from the Kremlin’s perspective, you see a consistent pattern of U.S. and western behavior amounting to a policy of regime change across Eurasia,” says Matthew Rojanksy, director of the Kennan Institute at the Woodrow Wilson Center. “Putin asks, if Washington can use force to topple regimes in Iraq, Afghanistan, or Libya, and can sponsor regime change by other means in Serbia, Georgia, and Ukraine, why wouldn’t Belarus or Kazakhstan or even Russia itself be next? Putin has to draw his own red line, and Syria is a good place to start doing so.”

“It’s not the whole story,” says Rojansky. “But it’s a big part.”

Most galling for Putin is evidence that America’s regime change agenda has crept into his own country. When mass anti-Putin demonstrations erupted in Moscow in late 2011, Putin quickly accused the U.S. of encouraging the protests. He lashed out specifically at Hillary Clinton for encouraging pro-democracy activists. “She set the tone, gave the signal,” Putin said in December 2011, charging that the U.S. was spending tens of millions of dollars “to influence our internal political process.”

Soon after, Russian state media accused the new U.S. Ambassador to Moscow, Michael McFaul, of being a subversive revolutionary agent. Pro-Putin commentators noted that McFaul is a longtime democracy advocate who has written of “Russia’s Unfinished Revolution,” and argued in a 2007 article that “even while working closely with Putin on matters of mutual interest, Western leaders must recommit to the objective of creating the conditions for a democratic leader to emerge in the long term.”