For more than a month, Secretary of State John Kerry has been pressing the regime of Vladimir Putin to accept what, for Moscow, would be a sweetheart deal on Syria. The United States would grant Russia’s long-standing request to carry out joint operations against Syrian rebels deemed to be terrorists, in exchange for another Kremlin promise to restrain bombing by the regime of Bashar al-Assad in some parts of the country. This cave-in to Putin would be so sweeping that some senior Obama administration officials have not concealed their doubts on whether Russia could be expected to deliver on any promise it made in Syria.

Sure enough, it turns out that Putin had other ambitions. Rather than settle for the partial victory offered by Kerry, Russia has joined with the Assad regime in a new campaign to drive all anti-regime forces out of Aleppo, the country’s largest city — a feat that would essentially win the war. Last week, Moscow unilaterally declared that it was creating four evacuation corridors out of rebel-held districts and invited the 300,000 civilians and armed combatants in them to evacuate. That assault is already underway.

The Russian operation was little more than a preemptory demand for the opposition’s unconditional surrender that ignored the ongoing U.N.-sponsored political process and violated a Security Council resolution. For their part, the rebels responded with a major offensive to break the Aleppo siege. On Monday, the deadline set by U.N. Resolution 2254 for an agreement on a political transition in Syria, some of the heaviest fighting of the year was underway.

Once again, the Obama administration appears to have been blindsided by Putin. On Friday, Kerry said he had been on the phone to Moscow seeking clarification about the Aleppo move, which he said posed the “risk, if it is a ruse, of completely breaking apart the level of cooperation.” By Monday, he had no answers.

Unfortunately, Putin has no reason to respect warnings from Kerry. Time and again, the secretary has declared that Russia must deliver or suffer consequences, such as a U.S. “Plan B” for Syria. Each time, Moscow has disregarded the jawboning — and Kerry has responded not with consequences but with new appeals for cooperation and more U.S. concessions. On Monday, he said, “We will see in the course of the next hours, few days, whether or not that dynamic” with Russia “can be changed.” But then, he spoke nearly the same words six months ago.

Editorial by The Washington Post