What was 9/11 if not military actions on USA own soils? Like, sure it can be labelled terrorism rather than "conventional military intervention", but psyops apart, on practical level that’s typical asymmetric/guerrilla warfare.
9/11 was not a military action against the USA, and the invocation of article 5 by the USA was illegimate.
9/11 was not a military action against the USA, and the invocation of article 5 by the USA was illegimate.