Troops are trained in rote set pieces, with no time devoted to improvising if things don’t go as planned. Military operations designed to take place sequentially—Step 1, then 2, then 3, etc.—fell apart, catastrophically. If Step 2 hit a big obstacle, the by-the-book soldiers moved on to Step 3 anyway. Therefore, large troop-transport planes tried to land, even though the airport hadn’t been completely secured and Ukrainian air defense systems hadn’t been destroyed. As a result, two Il-76 transport planes, each carrying 100 airborne troops, were shot down. Tanks aren’t supposed to roll through hostile territory all alone. They need...