At the outset of Russia’s invasion of Ukraine, most experts expected that Kyiv would fall quickly. Ukrainian forces were fighting against a military that was bigger and better armed. Russia’s troops had more combat experience and funding. The question was not if Moscow’s forces would depose the Ukrainian government but when regime change would happen. Of course, Kyiv didn’t fall. Instead, the Ukrainian military stopped Russia’s assault on the capital and forced a retreat. Russia downsized its initial mission from wholesale conquest, and the war now mostly consists of grinding offensives and counteroffensives in Ukraine’s east and south. The question...