There is no anti-war movement to speak of. There is, however, a small core of activists that like to think of themselves as the movement. Understandably, they have focused their attention on drones. This will continue to isolate them. Put bluntly, your average American doesn't give a shit about drones.
Most people, myself included, aren't terribly interested in the abstract legal justification or condemnation of U.S. drone use. (Domestic law almost always takes a backseat to perceived national security threats and many Americans scoff at the very notion of international law to begin with. How dare the rest of the world tell us what to do!) Morally speaking, Americans continue to support "the troops" when they shoot kids in person so it's highly unlikely they're going to be too bothered when some nameless, faceless Pakistani boy gets blown up via a command center in Nevada. Sure, drone attacks create more "terrorists," but so does smashing down doors in the middle of the night to stick a gun in the face of a guy who pissed off his local U.S.-backed warlord. Certainly drone strikes are less invasive than an occupying force.
The Obama Administration has taken Donald Rumsfeld's "light footprint" doctrine to a qualitatively higher, much more workable, level. The drones-based arms race is the only thing I can think of that might give the State Department and Pentagon a moment's pause. But, as we've seen in the past, that moment will be quick. The trick is to stay ahead of the curve. Other countries are developing their own drones. But by the time they're up to speed, we'll have bigger and better toys.
Yes, the possibility of drone use on U.S. soil will continue to rile up some people. Paranoid anti-government folks will unite with aging hippies, but to little avail. That isn't to say some unforeseen event couldn't happen and trigger a mass movement against our growing use of drones. No one knows the future. But as of now, drones are nearly perfect for exercising imperial force. Drones don't have families to deal with. They don't come back from combat all fucked up in the head. They do exactly as they're told.