Regardless of how people feel about Nevada rancher Cliven Bundy’s standoff with the federal Bureau of Land Management over his cattle’s grazing rights, a lot of Americans were surprised to see TV images of an armed-to-the-teeth paramilitary wing of the BLM deployed around Bundy’s ranch. They shouldn’t have been. Dozens of federal agencies now have Special Weapons and Tactics (SWAT) teams to further an expanding definition of their missions. It’s not controversial that the Secret Service and the Bureau of Prisons have them. But what about the Department of Agriculture, the Railroad Retirement Board, the Tennessee Valley Authority, the Office...