The Ukrainians are located in a north-south crescent between deep Russian lines in the southeastern Donbas region, and a potential pincer movement to their west.

Russian success in the southern port city of Mariupol, where its forces have been battling Ukrainian resistance for weeks, would free up thousands of Moscow’s troops to head north and potentially meet up with additional Russian forces heading south from the area around Kharkiv, in the country’s northeast…

It is anticipated that the battle will be fought at a distance. The Russians are using less armor than previously, without the blitzes that characterized some of their earlier forays into Ukraine, and returning to their more traditional doctrine of using artillery and other long-range fire.

Their front line in Donbas is heavily fortified with surface-to-air missiles that, from a Western perspective, underscore the belief that supplying the Ukrainians with more crewed, fixed-wing aircraft — despite their appeals for planes — would not enhance their prospects.