[G. Adams]

I'm afraid I don't know the details of this case, so please inform me if I make any mistakes?

Is Candian Oil nationalised or owned privately? If private, are the owners Canadian or foreign (particularly American)? If it's privately owned by a Canadian, then it is a Candian's oil to sell to whom he wants, not Canada's. If it's owned by an American, then it is an American's oil, not America's or Canada's. If it's nationalised, then it's the Canadian governments, and by selling the oil to the US you are making them dependant, in the short term, upon your oil.

My basic point is that the oil is the property of the owner, who should be free to trade with anyone, not that of the residents of whomevers territory it resides in.

As to whether the US would invade, it is unlikely. That supply could be gained elsewhere. As to whether they should invade depends really. If you cut off an American's ability to trade oil, if he owns it, with his customers then you are trampling over an American's right to his property, and an argument for some government action is justified (though actual invasion is still extreme, other measures could be used). If the Canadian government nationalised an American's oil then you are stealing (unless of course the American agreed to it, so he sold it to you). In which case, an argument for retributive measures could well be made.