Eh, history is long and moves in unpredictable ways. Just wait until the U.S. breaks up and Canada annexes the BosWash megalopolis and the West Coast, and then suddenly Canada will be policing the northwest passage again.
I can see the western states coming in to closer economic union with the west of Canada. I don't see Canadian influence dominating, though. There's too many people to the south. California alone has more people than all of Canada, for example. But there are common cultural elements from Canada all the way down to northern California. So a regional culture arising as a unifying agent, technically across country lines? I can picture it.
(SoCal is different, but that is neither here nor there in this case.)
There's that pesky Federal law that prohibits states from making their own arrangements with sovereign nations, but that does little to inhibit the actual flow of people or business.
