My mother's caregiver, Tamara, despises Vladimir Putin. She's a Georgian, and bitterly resents Russia's 2008 invasion of her home country and subsequent appropriation of South Ossetia and Abkhazia into Moscow's orbit. "That idiot Putin!" Tamara cries every time I visit my mom. Putin, she says, is determined to reconstitute as much of the Soviet Union as possible; now that he's carved off Crimea and eastern Ukraine, he will also find excuses to invade and swallow the three Baltic states. "If no one stops him," she says, "that idiot will keep going. You'll see." I used to think Tamara's fears were exaggerated, and that the pain of strong sanctions and a crumbling economy would deter Putin from further predations. But he has actually stepped up his aggression, with Russian state media predicting a direct military confrontation with the West — and warning that Russia might defend itself with a first-strike nuclear attack.

Putin's behavior would seem to be unhinged — wholly detached from a rational cost-benefit analysis. But his actions become explicable if you assume that his only goals are the preservation of his autocratic power — and the glorious restoration of Russia as the U.S.'s fully equal rival. If ordinary Russians must go hungry as a result, well, national honor requires sacrifice. In Putin's mind and in Russia's state media, the "expansionist" West stole Ukraine and is already at war with Russia. If the U.S. sends heavy arms to bolster Ukraine's outgunned army, will Putin see it as a proxy invasion and send Russia's full army streaming across the border? And then what do we do? As for that threat of Russia using tactical nuclear weapons — surely that's just a bluff. Isn't it, Vlad?