Neenah, Wisconsin, is a town of just over 25,000 people. In 2012, the town had a violent crime rate of 1.4 per thousandalmost one-third the national average. Of that year's 36 violent crimes, 32 were cases of aggravated assault; none were homicide. Neenah, Wisc., is, to put it modestly, a safe place.

So it seems difficult to justify the town's recent acquisition, reported in the June 8 New York Times, of a MRAP, or Mine-Resistant Ambush Protected armored vehicle, one of hundreds returning to America from tours of duty in Iraq and Afghanistan. And Neenah is not alone. Police departments large and small are acquiring, along with armored vehicles, M-16 rifles, grenade launchers, and more—the fully functional leftovers of two concluded, if inconclusive, wars.

The Times is a welcome, if belated, arrival to the cadre of observers voicing concern about the "paramilitarization" of American life—which is not confined to small-town police forces obtaining quasi-tanks. Why does the Department of Education have its own SWAT team? Why have IRS agents been spotted training with AR-15 semi-automatic rifles? And as the Times notes, the use of even local SWAT teams seems increasingly overzealous; just ask those unlicensed barbers.

No one is impugning the motives of police chiefs, such as Neenah's Kevin E. Wilkinson, who say they are acquiring the weaponry to save officers' lives; but good intentions do not necessarily make for good policy, and the transfer program smacks of a large-scale category mistake.

Military-grade weapons are designed and intended for military engagements. When a company of soldiers breaks down a door in Fallujah, their purposes are entirely distinct from those of cops doing the same back home. There is a marked difference—or at least there ought to be—between eliminating a holed-up enemy and serving a warrant. Because different ends suggest different means (a distinction America has always acknowledged, and often downright demanded), MRAPs and M-16s were made with Baghdad in mind, not Birmingham. But to provide military-grade supplies to police departments is to tempt the keepers of local peace to view their role as military, and their towns as battlefields. That is a dangerous confusion.

But the Times article suggests that some police chiefs may be viewing their cities just that way: cf. Sgt. Dan Downing's rather outlandish hypothetical. The suggestion is that, given the possibility of terrorism insinuating itself into American cities, every suburb is a potential battlefield. Ergo, stock the armories. But if cities are battlefields, then every citizen is a potential enemy combatant, and the police department is not defending against criminals but enforcing martial law.

None of this is to say that police departments ought not to be concerned with terrorism; ours is, in some ways, a brave new world. But there remains a crucial distinction between a state of war and even the worst instances of civil violence. War is hell, and military personnel are specially trained for it. Thirty-two counts of aggravated assault is unfortunate, but it is not war. Militarizing our police forces blurs the all-important line between war and peace—even a troubled, turbulent peace.

Cities are not battlefields, and our policemen are not soldiers. If the rest of us wish to remain citizens, we need to ensure that it stays that way.