According to a just-completed study by the New America Foundation, quoted in Mayer’s piece, Obama has authorized as many drone strikes in Pakistan in nine and a half months as George W. Bush did in his last three years in office — at least 41 C.I.A. missile strikes, or about one a week, that may have killed more than 500 people.

The dead have included high-value targets like Osama bin Laden’s oldest son and Baitullah Mehsud, the Taliban leader in Pakistan — as well as bystanders. Circling drones have struck panic. But as Mayer notes, “The embrace of the Predator program has occurred with remarkably little public discussion, given that it represents a radically new and geographically unbounded use of state-sanctioned lethal force.”

These are targeted international killings, no less real, and indeed more insidious, for their video-game aspect. The thing about robotic warfare is you can watch people get vaporized on a screen in Langley, Virginia, and then drive home for dinner with the kids. The very phrase “go to war” becomes hard to distinguish from going to work. That’s a conflation fraught with ethical danger. The barriers to war get lowered.

P.W. Singer, the author of an important new book called “Wired for War,” told me that, “We are at a breakpoint in history. The U.S. Air Force this year will train more unmanned system pilots than fighter and bomber pilots combined. And, as Bill Gates has noted, robotics are now where computers were back in 1980.”

Now you might think that a “pilot” sitting behind a computer bank in Nevada blowing away people in Afghanistan is less liable to combat stress than a soldier in a unit deployed there, but Singer said the opposite has often proved the case

It’s time for a reckoning, especially from a president who campaigned so vigorously against the “dark side” of the war on terror. Congressional review of the drone programs and the full implications of robotic warfare is essential to cast light and lay ground rules. The Obama administration should not be targeting people for killing without some public debate about how such targets are selected, what the grounds are in the laws of war, and what agencies are involved. Right now there’s an accountability void.

There are also broader questions. When robots are tomorrow’s veterans, does war become more likely and more endless? Do drones cow enemies with America’s technological prowess or embolden them to think America is not man enough to fight? What is the psychological toll on video-screen warriors?

There’s nothing innocent after all about the fluttering of a fruit fly’s wing.