"Today's decision brings the Fourth Amendment into the 21st century," Arthur Spitzer, legal director of the American Civil Liberties Union of the National Capital Area, said in a statement announcing the decision.
"U.S. citizens have a right to know what conduct may subject them to execution at the hands of their own government," Mr. Spitzer wrote. "Due process requires, at a minimum, that citizens be put on notice of what may cause them to be put to death by the state. ... Both the Constitution and international law prohibit targeted killing except as a last resort to protect against concrete, specific, and imminent threats."