I am on record having said a number of times the Cdn oil industry really does not need KXL if Line 3 replacement and TMX occur. Canada's oil production will barely fill both Line 3 replacement and TMX and it probably cannot find (afford) the capital to increase production enough to ever fill KXL. Even if oil prices could support all that capital investment, it would take at least 5+ years to do it, and by that time, climate change initiative will likely have permanently arrested demand growth. At best, I see KXL running full for a minimum of years, causing all sorts of financial headwinds for the producers that have committed to 20 year shipping contracts.
Even if TC sues with the pulling of the presidential permit, it will take years of litigation and AB will be on the hook with its equity interest and loan guarantee. Yet again, the AB taxpayer will take a thrashing..
There is some opinion out there that with the border crossing installed already (intentionally so before the US election this year), the rest of KXL is simply US interstate commerce regulated by FERC and the presidential permit is no longer relevant, and that a court would reject the concept that the WH can now 'stop' the pipeline. That could be technically true but the road ahead getting all the state and federal permits could face huge headwinds (inability to cross Federal Lands for example). That all said, I don't know enough about it to offer more than an armchair quarterback opinion.