It's very similar to Alberta tar sand, as I understand it, which Americanrefineries are set up for. Replace Canada's supply, then Canada can be safely invaded without danger to the oil supply, maybe.
Nor does it take back the fact that a huge percentage of the USA was enthusiastically on board with a violent takeover of a neighbouring nation. That was the scariest part. So many Americans would apparently happily march into Canada, or stand aside and watch it happening, and kill as many of us as it took to pacify us. Destroy our cities, take our land, turn us into another Puerto Rico or Cuba.
No. We'll fight to stop that happening.
No matter what happens now, the USA is no longer a friend and ally, no longer a partner.
The Heechee series by Fred Pohl uses a reasonable system, including relativity. A major plot point is that you can get into one of their magic ships, press the button, and pray your food halfway point holds out until the ship flips to brake.
I finally got around to watching it the other day. Genuinely good. Probably wouldn't watch it again, but yeah, solid.