one could make the case this is an act of war. And since Norway and Denmark are both NATO members, Bush can invoke article V of the NATO charter that says an attack on one member state is an attack against all of them…
Sadly, one can’t make the case. Article 5 reads:
The Parties agree that an armed attack against one or more of them in Europe or North America shall be considered an attack against them all and consequently they agree that, if such an armed attack occurs, each of them, in exercise of the right of individual or collective self-defence recognised by Article 51 of the Charter of the United Nations, will assist the Party or Parties so attacked by taking forthwith, individually and in concert with the other Parties, such action as it deems necessary, including the use of armed force, to restore and maintain the security of the North Atlantic area.
Note the added emphasis to this phrase: “in Europe or North America.” In 1949, Article 5 was written that way, quite intentionally, to keep NATO out of Europe’s brewing colonial troubles. Vietnam wasn’t a NATO affair, and neither was the Falklands War. 9/11, however, was and is.
Much as I’d like to argue in favor of invoking Article 5 against Syria, it just doesn’t work.