One of the problems with the US is they can shutdown a line at any time;
A current example being fought in the courts;
https://financialpost.com/commoditie...ut-down-line-5\\
Where the state of Michigan wants to cancel an easement and effectively shut down one of Enbridge's lines that has been there since 1953.
So...even if XL gets built, the leaf lickers will still try to shut it down at some later point.
Time to slowly close the valves to the US and force construction of a pipeline to other markets.