Four days after Vladimir Putin launched his war on Ukraine, it is apparent that things are not going the overconfident Russian president’s way. Russia has so far failed to take any of Ukraine’s major cities, disable its military communications or decapitate the government. The Russian Ministry of Defense’s own extended battle report on Sunday admitted for the first time to Russian dead and wounded — but claimed no major victories. In video of a meeting with Mr. Putin, Russia’s top two military chiefs looked stricken as he ordered them to place his nation’s nuclear forces into a “special mode of combat duty.”

The main reason for this situation — that offers a sign of hope and yet is fraught with danger — is the resistance of Ukraine’s army, bolstered by civilian volunteers, and by the inspirational leadership of President Volodymyr Zelensky. Yet Mr. Putin must also be perplexed by the unified support for Ukraine from the United States, the European Union, Japan, Australia and more. Democracies which waffled over tough sanctions and military aid only a couple days ago announced them Saturday and Sunday with defiant certitude: expulsion of Russian banks from the SWIFT payments system and blockage of Russian central bank reserves; lethal weapons shipments to Ukraine; ouster of Russian airlines from European airspace. BP will disinvest from Russia’s state oil company; the E.U. will bar Russian propaganda’s TV outlets.

In a dramatic speech to Germany’s parliament, Chancellor Olaf Scholz announced that Germany will not only arm Ukraine’s forces, but rearm its own, committing to spend more than the NATO minimum of 2 percent of its economic output on defense. Mr. Scholz urged a shift from Russian energy supplies to other sources. These are extraordinary changes in Germany’s postwar foreign policy and security posture, but Mr. Scholz — correctly and courageously — said Mr. Putin’s war is “a turning point in history” to which Germany must swiftly adapt. The applause that greeted Mr. Scholz’s words was the sound of a mature democracy, Europe’s richest and largest, dealing a strategic defeat to the Kremlin’s decades-long effort at co-opting it.

Mr. Putin interprets the West’s firm response as evidence of hostility to Russia, not proof that he made a bad bet on democratic decline and disarray. Issuing his nuclear order, he cited the West’s “aggressive statements.” The practical effect of this alert remains unclear; the Biden administration rightly both condemned it and expressed confidence in the United States’ deterrent capability. However, the blunting of Russia’s initial military thrust might increase Mr. Putin’s desperation and prompt him to try to break Ukraine’s will through increased and even less discriminate shelling, rocket and missile fire.

The next step for the United States is for Congress to move quickly on a bipartisan aid plan when it returns this week. The White House is requesting $6 billion, though independent estimates suggest Ukraine’s military and humanitarian needs call for around $10 billion. As they deliberate, lawmakers should consider these data from a new Washington Post-ABC News poll: Sixty-seven percent of American adults favor sanctions against Russia. More than half of adults said they would support sanctions even if it meant higher energy prices. Between the resistance of the Ukrainians and the unity of the West, Mr. Putin appears baffled. Congress should add to his troubles.