"U.S. commitment to NATO’s Article 5, under which an attack on one alliance member is considered an attack on all." It needs a qualifier. Specifically,

(If a member of NATO attacks another country, that NATO country is responsible for the consequences.)

The first time that Article 5 was used was to help the US in a war that started with the attack on Palestine to take land for Israel. Financed by the US. Arms supplied by the US.

There was an exchange of battles. 

9/11 was the Arab response on US soil to the US attack on Arab soil. The Arabs tried to take out the heart and soul of the US, its financial district and the Pentagon. It failed.

Unfortunately our media concentrated on the loss of civilian lives, which indeed was horrendous. However the loss of lives in Palestine far exceeded the losses in 9/11. 

Canada should insist on Article 5 be modified so that if a member of NATO attacks a country, that NATO country is responsible for the consequences.