evidence: At the gathering of Ukrainian leaders and U.S. and European policymakers, called the Yalta European Strategy, over the weekend, Ukrainian leaders pushed the military and moral argument. We, they said, have to defend ourselves against a Russian escalation of drone and missile attacks launched from across the border. Also, it’s always good to make the Kremlin worry more about what else Ukraine will — and can — do to bring the war to Russia. Ukraine used Western-supplied missiles to push back Russian forces from Crimea, the Ukrainian region annexed by Russia where Kyiv isn’t prevented from using them. Ukraine already strikes deep in Russia with drones and is developing its own missiles.