That kind of precision is becoming more important. Twelve years ago, the Department of Defense observed that our armed forces were increasingly being used for peacekeeping, humanitarian aid, and protection of civil society. More of our enemies were blending in with, or disguising themselves as, civilians. Through the media, more eyeballs, hearts, and minds could see the infrastructure we destroyed. The DOD proposed the development of weapons "to incapacitate personnel or materiel, while minimizing fatalities, permanent injury to personnel, and undesired damage to property and the environment."

Like lethal weapons, nonlethal weapons have evolved from short- to long-range. Batons and pepper spray required hand-to-hand combat. Water cannons, rubber bullets, beanbag rounds, and sting ball grenades have extended our reach, but not far enough to keep soldiers clear of rocks or small-arms fire. Some of our weapons are insufficiently discriminate. Tear gas torments a whole crowd, not just the miscreants using it for cover.

Projectiles are also unpredictable. At long range, particularly in crosswinds, rubber bullets can hit the wrong people, or the right people in the wrong places. At close range, they can kill. Look at the absurdly named "FN303 less lethal launcher." It's supposed to fire "non-lethal projectiles at established non-lethal ranges." But when you're launching things, less lethal is the best you can do.

That's where the pain beam comes in. Unlike projectiles, beams are "directed energy." They travel in a straight line over long distances, ignoring gravity and wind. They cause no more damage at 10 feet than at 1,000. Unlike gas, they're discriminate. Raytheon, the pain beam's manufacturer, points out that the weapon "allows precise targeting of specific individuals" and that the pain "ceases immediately" when the beam is diverted or the target flees.