> it was logistically impossible. The importance of logistics for large armies is widely underestimated. If you abandon your supply base, and try to live of

> it was logistically impossible. The importance of logistics for large armies is widely underestimated. If you abandon your supply base, and try to live of the (enemy's) land, you have to advance continuously and quickly, like Sherman's successful campaign in Georgia and the Carolinas. If you rest for even a day or so, you deplete the available "forage" (i.e. the resources of the civilian population). If you stick with your supply base, then a large part of your force has to be devoted to defending the supply lines; and those supply lines have to be manned, and consume supplies themselves. In the time before internal combustion engines, it was hard to maintain supply lines for armies larger than about 80,000 men, because the fodder required for horses began to exceed the supplies needed by the soldiers. Putin ran into logistics problems almost immediately; Russia depends internally on railways very heavily, but his army had to de-train at the border and switch to trucks, on narrow roads, lined with forests.