nato is not a unified block run by a dictator. i know ziggers think this because they cannot understand the concept of freedom. no nato nation is forced to do anything at any time. even if article 5 is invoked no nation is forced to do anything. they are to consider it an attack on their own country, but their response is entirely up to them and that includes a response of "doing nothing", only sending financial aid, all the way up to sending soldiers to the front lines. it's up to the individual countries to decide.
United States