Putin has not received the memo on 21st-century behavior. Neither has China's president, Xi Jinping, who is engaging in gunboat diplomacy against Japan and the weaker nations of Southeast Asia. Syrian president Bashar al-Assad is waging a very 20th-century war against his own people, sending helicopters to drop exploding barrels full of screws, nails and other shrapnel onto apartment buildings where families cower in basements. These men will not be deterred by the disapproval of their peers, the weight of world opinion or even disinvestment by Silicon Valley companies. They are concerned primarily with maintaining their holds on power...Obama is not responsible for their misbehavior. But he does, or could, play a leading role in structuring the costs and benefits they must consider before acting. The model for Mr. Putin's occupation of Crimea was his incursion into Georgia in 2008, when George W. Bush was president. Mr. Putin paid no price for that action; in fact, with parts of Georgia still under Russia's control, he was permitted to host a Winter Olympics just around the corner. China has bullied the Philippines and unilaterally staked claims to wide swaths of international air space and sea lanes as it continues a rapid and technologically impressive military buildup. Arguably, it has paid a price in the nervousness of its neighbors, who are desperate for the United States to play a balancing role in the region. But none of those neighbors feel confident that the United States can be counted on. Since the Syrian dictator crossed Mr. Obama's red line with a chemical weapons attack that killed 1,400 civilians, the dictator's military and diplomatic position has steadily strengthened.
