From The Salt Lake Tribune, September 13, 2001: "Washington's NATO allies declared Wednesday that the terrorist attacks in New York and Washington, D.C., can be considered an attack on the whole alliance if they were directed from abroad. 'An attack on one is an attack on all,' NATO Secretary-General Lord Robertson said after the alliance's ambassadors decided to invoke Article 5 of the NATO charter for the first time in the alliance's history." (Base your answers strictly on formal logic.)

a. Trace the formal logic of the text.
b. In your opinion, is an attack on the US an attack against all NATO allies?
c. In light of Robertson's claim that "an attack against one is an attack against all," what is the logical inference of the statement that, "the alliance's ambassadors decided to invoke Article 5 of the NATO charter for the first time in the alliance's history"?