The Ukraine-Russia war is nearly a year old with no end in sight. Both Kyiv and Moscow eschew negotiations and seem prepared to endure a brutal war of attrition. The U.S. provided more than $100 billion in military and economic support for Ukraine and pledged to arm and aid them “for as long as it takes.”

What lessons can be drawn from the fighting so far? What is the current military balance—particularly with Russia’s mobilization effort and U.S. and European tanks on their way to Ukraine? Does either side have the capacity to mount a sustained offensive? What do the next few months hold for Ukraine, Russia, and the West, and could fighting in the spring prove decisive? What circumstances could bring escalation—whether through the use of nuclear weapons by Russia or the spread of the fighting to Crimea or NATO countries?