B-Jay we export 2.5M bbl/d to US. Eastern Canada can use 700,000 bbl/d of this but Canada doesn't have the infrastructure, as up to the last year it was cheaper for them to import from Middle East.
The Asian market would simply add another outlet to the growing supply Alberta is producing, most likely about 500,000 bbl/d. This would not hurt the US, it might actually help bring Brent down, that in itself would help the U.S. immensely. I can see Brent coming closer to WTI with the Keystone XL moving forward. I also think a pipeline to Eastern Canada would happen before the Gateway pipeline to Kitimat. The First Nations carry a lot of clout, maybe too much.