Assault-style raids have even been used in recent years to enforce regulatory law. Armed federal agents from the Fish & Wildlife Service raided the floor of the Gibson Guitar factory in Nashville in 2009, on suspicion of using hardwoods that had been illegally harvested in Madagascar. Gibson settled in 2012, paying a $300,000 fine and admitting to violating the Lacey Act. In 2010, the police department in New Haven, Conn., sent its SWAT team to raid a bar where police believed there was underage drinking. For sheer absurdity, it is hard to beat the 2006 story about the Tibetan monks who had overstayed their visas while visiting America on a peace mission. In Iowa, the hapless holy men were apprehended by a SWAT team in full gear.

Unfortunately, the activities of aggressive, heavily armed SWAT units often result in needless bloodshed: Innocent bystanders have lost their lives and so, too, have police officers who were thought to be assailants and were fired on, ...

SWAT teams have their place, of course, but they should be saved for those relatively rare situations when police-initiated violence is the only hope to prevent the loss of life. They certainly have no place as modern-day vice squads.

Many longtime and retired law-enforcement officers have told me of their worry that the trend toward militarization is too far gone. Those who think there is still a chance at reform tend to embrace the idea of community policing, an approach that depends more on civil society than on brute force.