One hundred days of all-out war has been plenty of time to get acquainted with the Russian troops. Their lackluster combat performance, artillery barrages against cities, treatment of civilians, intercepted messages home, and interviews with dozens of civilians around Ukraine allow one to put together a mosaic portrait of the invaders. It’s not a flattering image. Many of the soldiers are dirt-poor and badly educated, with many growing up without access to modern amenities. Many joined the armed forces because they have no future in their backwater towns. The majority have bad training, low morale and no faith in their...