Suppose a NATO country makes a first-strike against a non-NATO country. If that non-NATO country strikes back in an armed attack, is that considered an attack against all NATO countries? In other words, would an armed attack on a NATO country that is a retaliatory strike trigger Article 5? http://www.nato.int/cps/en/natolive/official_texts_17120.htm Consider the phrase " if such an armed attack occurs, each of them...will assist the Party or Parties so attacked by taking forthwith...such action as it deems necessary...". The use of "will assist" instead of "shall assist", and the phrase "...as it deems necessary" -- do these phrases give an out to NATO to not attack?