The Army built the Apache to kill tanks, but the drone war is proving it may need to start hunting the cheap flying threats now bleeding air bases and exposing a dangerous gap in U.S. doctrine.

The US has deployed A-10 Warthogs attack jets, Ah-64 Apache helicopters, and 5,000-pound ground penetrator bombs to take out Iranian drones, boats, and mines to help secure the Strait of Hormuz, ...