Leaving aside the 'wisdom' of hauling petrol products through congested, storm tossed, environmentally fragile waters on tankers built and operated by the lowest bidder..... What incentive does Canada now have to have those products refined by a nation that actually has effective environmental laws?
The tar sands are getting all of the press, because people somehow think that you guys are just going to leave it in the ground if they can't process it in Illinois and on the US Gulf Coast. I'm thinking that Keystone would have transported both, but that's an "I think." I fix phones for a living. I have kin that do the petrol thing (exploration AND production) but every since "fracking" became a word used by people who never saw Battlestar Galactica the folks in Houston have plenty to do without Keystone. One of the concerns about transporting tar sands stuff through Keystone is that you have to heat it up first making it less carbon neutral than heating it up anyway to put through a different pipe and then putting it on a (fossil powered) ship and taking it somewhere else. But hey... NIMBY. Americans unfortunately just aren't that bright. Keystone=Trump=bad. MUCH worse than....say....another oil tanker on the rocks. The good news is that the crude leaks out faster than the play-dough does.....so troweling the tar sands product into a tanker hull will probably JUST be a carbon neutrality failure for the world and an economic hit for the USA rather than the next cause for oil blackened coastlines in the Gulf of Alaska.... ...."hopefully"
The argument against KeystoneXL wasn't just environmental, but also about land ownership rights. TransCanada originally suggested the pipeline, in part, because it would be easier to seize the land in the US than in Canada for other pipeline routes. When a wealthy community voiced opposition to the original route of KXL going near them, the planners decided to go through a Reservation. The environmental arguments weren't all about climate change. A big part of that was the local risk to aquafiers. The opposition to KeystoneXL started under Bush when the project was started. It is Canadian oil, and the pipeline was going to profit Canadian companies. I don't think American citizens should be paying in land and environmental rights for it. India had proposed building a refinery to process the tar sand crude. Fastest tanker travel would be through the Atlantic, and it doesn't look like Quebec is going along with pipelines through their lands.
