I have been wondering about this idea for a little while, and I'm trying to use it in a potential TL. So what if the US wasn't able to reach the Pacific. Like if Texas chose to remain independent (as out there as it might be) and Britain was able to gain it's entire claim in Oregon. The US is then boxed in but then what really happens to the concept of Manifest Destiny? Does the US sort of let it go, or do they begin something similar to state sponsored filibustering to try and gain it through other means? Or would it be something between the two?