Ukrainian soldiers pass on top of armored vehicles next to a destroyed Russian tank
in the outskirts of Kyiv, March 31. PHOTO: RODRIGO ABD/ASSOCIATED PRESS

As Russia’s war on Ukraine enters its sixth week, the script has flipped. Russia’s advance has stalled, and Ukraine now wants to go on offense to push back Russian forces from the land they’ve taken. But the country needs U.S. and NATO help to do it, and it seems the Biden Administration is reluctant to provide those weapons and intelligence.

In her Wednesday press briefing, White House communications director Kate Bedingfield said no fewer than eight times that Vladimir Putin had committed a “strategic blunder” or “mistake” or “error” by invading. That’s the White House line to suggest that the West is winning against the Russians.

But that sure sounds like a premature declaration of victory. His forces are still bombing Ukraine’s cities and they have grabbed more territory. Mr. Putin could still emerge with a strategic advantage in the medium- to long-term if he strikes a truce that leaves Russia in control of a large chunk of Ukraine.

The peace terms Russia is demanding in negotiations suggest that such a consolidation in Ukraine’s east and a long-term occupation is now Russia’s goal. He’ll have won the long-sought “land bridge” between the Crimea and the Donbas.

Mr. Putin could claim victory, pause for some years while he re-arms, continue trying to assassinate Ukrainian President Volodymyr Zelensky, and otherwise make political, cyber and other trouble for a Western-leaning Ukraine government.

That’s why Mr. Zelensky now wants to go on the offensive. The more territory his forces can win back, the stronger position his country will have at the bargaining table. The experience of Russia’s behavior in Georgia in 2008 and eastern Ukraine in 2014-15 is that Mr. Putin doesn’t give up territory once his troops occupy it. The result is another “frozen conflict,” with the country he has invaded weaker than before and more vulnerable to more Russian mayhem.

The Ukrainians need heavier weapons to go on offense, including tanks and fighter aircraft like the MiG-29s that Poland wants to provide under the political cover of NATO. It also needs intelligence on Russian troop movements and vulnerabilities in the east. Now is the time to help Ukraine take the offensive. Reports of demoralized Russian forces are more frequent, including defectors who have taken equipment with them.

But in a private briefing on Capitol Hill this week, Administration officials continued to resist bipartisan pressure to provide heavier weapons. The claim is that they won’t make much difference to the conflict, but the Ukrainians are a better judge of that. It’s much harder to dislodge dug-in tank battalions with infantry armed with hand-held Javelin antitank missiles than it is with tanks or aircraft that can strike from above.

The concern among Ukraine’s supporters on Capitol Hill and the Pentagon is that the Biden Administration doesn’t want Ukraine to go on offense. It wants a negotiated settlement as soon as possible. France and Germany, the doves in the NATO coalition, are in a similar place. They worry that if Russia suffers even greater losses, Mr. Putin might escalate again and perhaps in more dangerous ways that drag NATO directly into the war. In a sense, Mr. Putin with his threats is defining the limits of U.S. assistance to Ukraine.

But the U.S. and at least some NATO countries won’t be able to ignore Ukraine even if there’s a truce or frozen conflict. Mr. Zelensky will have to sell any agreement to the Ukrainian public, who won’t be eager to concede territory after thousands of innocents have been killed. The Ukrainians are going to want security guarantees from the West, lest they be vulnerable to future Russian attacks.

One idea that deserves to be considered is a mutual-defense pact of the kind the U.S. has in the Pacific with Australia and Japan. After all that Ukraine has sacrificed, Mr. Zelensky won’t settle for Mr. Putin’s nonaggression promises, and President Biden shouldn’t lean on him to do so.

Throughout this conflict, the Biden Administration has been slow and reluctant to give Ukraine the weapons and intelligence support it needs. Pressure from the public and Capitol Hill has forced its hand. Now, with Russia on the defensive, is the time to keep the pressure on to truly achieve a strategic victory for Ukraine and NATO.