Serhii, a 46-year-old Ukrainian army officer who ran a furniture store in civilian life, has survived four years of war against Russia. These days, he commands a battalion of 300 troops in Ukraine’s front-line city of Sloviansk. After two combat injuries and the loss of many friends, his take on the war is anchored in harsh experience.

So it is all the more striking to hear his assessment of where things stand. “We’ve reached a turning point,” he told me during my visit to Sloviansk in late June. The Ukrainians, he said, are striking devastating blows against Russia’s energy infrastructure, vital logistics, and the factories that produce critical components for its high-tech weaponry. He particularly applauded Kyiv’s campaign to sever the supply lines that provide Russian forces in occupied Crimea with ammunition, fuel, and food. So how long will it take to cut off the peninsula entirely? “I think we can do it by the end of the summer,” he answered, noting that this would be a huge humiliation for Russian President Vladimir Putin, who has cited Russia’s 2014 seizure of the Ukrainian peninsula as one of his lasting achievements.

Serhii, a 46-year-old Ukrainian army officer who ran a furniture store in civilian life, has survived four years of war against Russia. These days, he commands a battalion of 300 troops in Ukraine’s front-line city of Sloviansk. After two combat injuries and the loss of many friends, his take on the war is anchored in harsh experience.