NATO has been much praised “an attack against one Ally is an attack against all”. 

The US financed the takeover of land in Palestine from Arabs. When the Arabs responded by attacking the US, 9/11, all NATO countries were committed to helping the US. 

Thus 159 Canadian soldiers died in combat and 10, including Lionel Desmond with PTSD. Then the three he killed.

Article 5 needs an addition such as “an attack by a member that has not been attacked means that member is on its own, is responsible for the consequences.”