"The standoff in the Persian Gulf underscores both a lasting and frightening shift on the modern battlefield," author Scott Anderson suggests. "While specific, critically important sites can undoubtedly be made drone-proof " the White House, for example " defensive shielding on a large scale is impossible, as Israel has now discovered with its much-vaunted and much-punctured Iron Dome."

Given the simplicity and cost of the weaponized drone, every one of the world's geographically strategic choke points " the Panama and Suez Canals, the Strait of Gibraltar and the airspace over New York " is now vulnerable to attack by a hostile force that has the ability to build such a weapon and a willingness to suffer the consequences. Alarmist? Think of some of the apocalyptic regimes or murderous guerrilla groups of the recent past " the Baader-Meinhof Gang in West Germany, or the Khmer Rouge in Cambodia, or bin Laden's Al Qaeda " and imagine what they might have done with a $2,000 weaponized drone.