Maybe I'm wrong, but with the river north of the Ukrainian border, it seemed like they wanted that as new easier to maintain defensive line. The defenses in th

Maybe I'm wrong, but with the river north of the Ukrainian border, it seemed like they wanted that as new easier to maintain defensive line. The defenses in the north were affected by incompetence or corruption, so the push north came across a little like shoring up their positions to need fewer men in the long run.