Putin’s machismo leads him to underestimate his adversaries and show off for domestic and international consumption. Unsurprisingly, his favorite tactic is unprovoked aggression—in other words, the bluff. He got away with it in Georgia in 2008, Syria from 2012 onward, in annexing Crimea in 2014 ...Yet last month, he was caught completely off guard when the West finally called his biggest raise ever. As boxer Mike Tyson said, “Everybody has a plan until they get punched in the face.” The West’s reactive jab of sanctions and aggressive arming of the Ukrainians appear to have completely stalled—and now reversed—Russia’s advance on...