Since World War II, the world had thought that we were building a global consensus that abjured the wars of aggrandizement waged by Hitler, Stalin and others. Yet in 22 years in power, Vladimir Putin has repeatedly opposed international rule of law with attacks on smaller neighbors. Putin’s own behavior under pressure and the patterns shown by his dictatorial predecessors make clear that, as Ukraine’s resistance reveals his lies and threatens him with embarrassing setbacks, his likely response will be to escalate with only more massive violence.

Ukrainians’ Increasing Danger

So the United States, its allies and the world’s other democracies must look ahead, grimly, to what Putin, as a cornered bully, may do. Wrenching precedents are on record. One of Putin’s first acts in power was a renewed war in the region of Chechnya. Russia bombed and shelled its capital, Grozny, into rubble, burying tens of thousands of Chechens and Russians alike in the city-sized field of debris. Russia brutalized the Syrian city of Aleppo similarly in 2016. Now, with its ground assaults into Ukraine largely stalled, Russia’s shelling and bombing of Ukrainian cities has increased. Ukrainians—probably more than 3 million in Kyiv and 1 million in Kharkiv for example—face a heightened risk of massive atrocities.

With the Ukrainians thus forced onto the front line of defending our human ideals of democracy and rule of law, the world must now sustain them through what is coming. Our first days’ witness of their ordeal has triggered an outpouring of support. Nations like Germany, Finland, Switzerland and Sweden have stepped forward in new ways, offering various combinations of diplomatic and economic support and weapons that Ukrainians now sadly require. Poland, Slovakia, Romania, Moldova and other nations are welcoming 1 million Ukrainian refugees so far—the kind of humane response that we should always provide for people displaced from their homes.

The world’s community of democracies must stay this course, knowing full well that the costs to us for doing so will rise. Led by a courageous president, Ukrainians’ defense of their independence—and of our ideals—will now require the efficient re-supply of defensive lethal weapons and ammunition that Ukrainian officials say already are running short. Among the most critical, the officials say, are anti-tank defenses such as the U.S.-made Javelins and Swedish AT-4s, protections against air attack—Stinger and air-to-air missiles—and protection against Russian jamming of Ukrainians aircraft communications. Speed is urgent and supply routes, mainly overland, must be organized.

New Realities for Russia

Ukrainians, while massively overmatched by the destructive power of Russia’s army, will continue their resistance. Their casualties are growing—and so will the losses to Russia of its mostly young soldiers. After a week of the evidence from Ukrainians’ cellphone videos, Russia conceded for the first time Wednesday that its soldiers have been killed. Vladimir Putin’s Kremlin is ill prepared for this. When Putin began his invasion of Ukraine in 2014, at least 200 Russian fighters were killed in the first months, and the Kremlin enforced secrecy around those deaths to avoid public questioning over its choice of war.

This time, secrecy will be impossible. Russians’ protests against the war have begun, and they will only multiply as the bodies of the dead come home and as Russians pay the rising economic costs of war, sanctions, and their nation’s growing pariah status. Ordinary Russians are facing rising prices for basic goods, a plunge in the value of their currency and the risk of seeing their savings disappear.

Thousands of Russians already have protested in the streets—a courageous act in an authoritarian state where dissenters often wind up detained or dead. Tens of thousands have signed antiwar petitions from groups across Russian society: intellectual leaders, economists, doctors, classical musicians and others. Some have been fired from their jobs as a result. Protest has come from those close to the government and its foreign relations, such as a leader among retired military officers and graduates of the foreign ministry’s own school of diplomacy. Former foreign minister Andrei Kozyrev has urged Russian diplomats to resign in protest over the war.

Unity and Diplomacy

The remarkable unity and speed of the international response to Russia—the sanctions, help for Ukraine and its refugees—will be tested and re-tested in coming months. Russia will find sinuous paths to circumvent sanctions, and those escape routes will need to be blocked. The billions of dollars in costs to our own economies and budgets—from sanctions, humanitarian relief and Europe’s worst war in generations—will steadily rise. Americans, Europeans and others should soberly recognize this and prepare.

Maintaining unity among ourselves will require more of what Ambassador Douglas Lute recently called our “diplomatic surge.” And that diplomacy will require, too, that we keep the door open to a realistic dialogue with Russia. Our continued message to Russia and its bewildered citizens must be that global resistance, sanctions and unity are not a threat to Russia’s security, but are a defense—of Ukraine, Europe and the safety of all nations from the menace of unprovoked wars.

Ukrainians are united as never before in defense of the independent nationhood and democratic choice that Putin declares fictional. He will multiply the violence and death with which he is trying to enforce his misconception, but warfare will not erase the Ukrainians’ national vision or their will to protect it. All of us who hope for our children to live in a more just, peaceful world must remain humbled by the sacrifices that Ukrainians now make on their own behalf and on ours. We must be ready for the infinitely smaller sacrifices required of us to assist them.