When a combined force of 40,000 Russian troops launched an assault across Ukraine’s northern border with Russia on May 9 – that’s Victory Day, the day Russians celebrate the Soviet defeat of Nazi Germany in World War II – observers tried to understand the Russians’ aim. Was the goal to drive on Kharkiv, Ukraine’s second city just 25 miles south of the northern border? Was it to capture a string of border settlements in order to push Ukrainian troops, and their artillery, farther from Russia? Was it to convince the Ukrainians that either of the above was the goal –...