The Columbia Drainage Basin east of the Cascades could be made into its own state - American Columbia. The Snake Drainage Basin could be separated from American Columbia into its own state. Perhaps, it could be the Snake Drainage Basin upstream of the confluence of the Snake River and the Clearwater River. Make sure Idaho still gets Lewiston. I also petition to rename Idaho to Snake, or failing that Great Pocatello.
If having Golden, BC, Missoula, MT, and Bend, OR all in one state is too much another state could be carved out of the Columbia Drainage basin between the Cascades and the Yakima River Watershed. I don't think this is necessary.
The land west of the Cascade Divide, north of the Umpqua Drainage Basin, and south of the middle of the Columbia River is ideal for Oregon, though it is a rump version of the OTL state. It wouldn't be a bad idea to add the the Cowlitz/Lower Columbia Drainage Basin, and the Southwest Washington Drainage Basin to rump Oregon. The southern boundary of the Fraser Drainage Basin should be the the northern border of Washington state.
Fraser River Basin Map
The remainder of southwestern OTL Oregon can be divided between Jefferson, Sacramento/Northern California, or Nevada as appropriate.
I could draw this in mspaint if anyone is interested.
In this time frame the USA has the potential to come out on top. It would be a stupid, pointless war, I think we (Americans) would screw up the prosecution and aftermath of it.
That would be great, by all means, draw it in MSPaint.
So, the lucky thing for the Americans is, war is unlikely, even if they push for bigger claims, Britain can't afford a war on the far side of the world - there was chaos in Europe at the time, simmering discontent in India, and the Russians were eying the Balkans with alarming intent.
The downside to being a global empire is that your attention is divided along many fronts, while the USA, only has two: north and south.
That said, the whole 54 may not be attainable, not at this time - 52 is about the Northern limit I think the Americans can push for, and that's likely with a cash payment to the British.
Now where do things go from here with a USA-British North America border set farther north west of the rockies?
For one, it likely cripples any hopes of a Canada that spans to the Pacific - what's left of British Columbia offers poor harbors, and especially if the Americans buy Alaska, it becomes utterly indivisible. Likely, we see the Brits sell America everything west of the Continental Divide ala the Gadsden Purchase.
Thus, we get a USA that controls the entire Pacific coast, which may result in a much bigger focus on the Pacific for the USA.
Conversely, any Canadian confederation is going to develop radically different with a cut off at Alberta. Hell, does a united Canadian identity even develop as we would know it?
All of this speaking has made me go implement it on Victoria II. I know it’s only a game but the AI got distracted, (intentionally or unintentionally) Britain got into a war with Russia and this allowed me to colonise British Columbia and also a good portion of central British America.
Playing this has prompted me to think that if the Americas did get 54-40 they may have gone onto claim other territories. However, it is interesting how the Americans and the UK entered diplomatic dialogue to resolve this contentious issue and that the British must have known that if they did give the Americans 54-40, this would have shattered any future nation emerging. As you can see from the image above, the US just utterly dominates.
I must admit, of all the reading, I did not see what Polk did in the American-Mexican war, which was offer money in an attempt to gain territory. Thinking of it now, I think it is the only possible solution to gain 54-40 without war. This is a fantastic source. It shows all the concession lines drawn in the American-Mexican war.
Polk informed Trist to acquire New Mexico and Upper California and, if possible, Lower California. For the three states he was to pay not more than $25,000,000 and for the two not more than $20,000,000. (Dated April 15, 1847) - Source:
http://dsl.richmond.edu/historicalatlas/94/a/?sidebar=text&legend=hidden&view=plate
We can extrapolate the following from what he offered in negations with Mexico:
One has to consider California, New Mexico and Lower California were derelict at this point. Therefore Polk was buying the land based on its actual size. The table below shows a list of regional districts areas in British Columbia. The red columns indicate districts that overlap the 54-40 parallel whilst the green boxes are a ballpark figure for those districts that were apart of this districts but south of the 54-40 parallel.
Estimating the area south of the 54-40 parallel to be about 707,295 square miles, you can estimate the amount of money he would have offered. For Lower California, New Mexico and California he offered $25,000,000 for 341,522 square miles. Therefore 341,522 x 2 = 683044, this is $50,000,000. The 24,251 square miles value could be anything between 1 and 3 million. In conclusion, he would pay anything between $50-$53,000,000 million dollars for 54-40. Offering this money would hopefully appeal to the chaos in Europe, discontent in India, and Russian Balkan annexation. If he had got 54-40 his presidency would have far-reaching consequences.