That means following Mr. Zelensky’s lead on what Ukraine is willing to accept. Ukraine has earned the right to determine what concessions, if any, it can live with. The Ukrainian president has already taken NATO membership off the table, but he understandably is refusing to concede Russian control over Ukrainian territory. No one in the West should pressure him to accept such terms.

The U.S. and Europe can also increase the sanctions pressure on the Kremlin. Sanctions on Russian energy sales still aren’t in place, though they would hurt Mr. Putin’s war financing the most. Sanctions relief for Russia shouldn’t even be on the table until Mr. Putin withdraws his tanks and concedes Ukraine’s right to be an independent state.

What should be on NATO’s agenda is why Western intelligence misjudged the war. The CIA did very well in anticipating that Mr. Putin would invade, but it vastly overestimated the ability of his military to conquer Ukraine. That pessimism may have convinced President Biden that more military aid earlier wouldn’t have made a difference. Congress’s intelligence committees should investigate.