I'm not entirely sure they can sue this due to jurisdiction issues.
Plus they are the American Civil Liberties Union, Not only are the targets NOT american, the dont really have Civil Liberties either.
Im assuming the pilots behind the UAVs have target criteria, and need to provide evidence of said criteria to receive permission to eliminate the target.
Excuse me for the muslims to not respect the geneva convention, not be uniformed, and the fact they take pleasure in hiding behind their families or neighbors, sick, injured or children. When a few individuals fire at you from a crowded market, you want me to just sit there and deal with being shot at and possibly die, FU ACLU.
Also, whats the word we can take from those countries that they were actually civilians? Someone carrying a gun is militia, someone who died carrying a gun was a soldier, but in the time it takes to get a team in there to confirm kills, those guns disappear and now proof of militia is gone and so they are just civilians now. I doubt the Civilian casualties are actually as high as they are perceived. I think it usually is militia, but someone else picks up the gun and takes their place.