According to the Northern Command official page, the purpose of this agreement is, "Unity of effort during bilateral support for civil support operations such as floods, forest fires, hurricanes, earthquakes and effects of a terrorist attack, in order to save lives, prevent human suffering and mitigate damage to property, is of the highest importance, and we need to be able to have forces that are flexible and adaptive to support rapid decision-making in a collaborative environment.”

The agreement, defined as a Civil Assistance Plan, was not submitted to Congress for approval, nor did Congress pass any law or treaty specifically authorizing this military agreement to combine the operations of the armed forces of the United States and Canada in the event of a wide range of domestic civil disturbances ranging from violent storms to civil riots.

Wouldn't their soldiers on our land be tantamount to invasion? And how could this be a law of the land without approval of the Legislative branch?

Why doesn't he (Bush) just declare himself King, and get it over with? But would it be enforceable?