ORIGINAL: engineer
Let me second String's comment of "Hear, hear!"
Thanks
There are any number of historical "levers" that one can pull in laying the ground work for a scenario. The late scenario in WPO is the most at risk since the mostly historical OOB for non-capital ships would have certainly been influenced by the increased expenditures for the battleships.
Agreed, everything is interlinked. The battleline is only a fraction of spending (admittedly a rather large one). It needs cruiser and destroyer consorts, they all need logistics support and so it goes on. And if you grow stronger then your opponent must grow to match. And if you grow and they grow then everyone else must. And of course if you fund the Navy then the Army and the Air Force will also want their share.
1) Head in the sand: Politicians in the West look after other things and Japan's attack is a "bolt from the blue" surprise. This explains the unpreparedness of the western forces. However, without Washington would the US have mothballed all those recently completed destroyers, the RAF demobilization, etc.
This is one I just don't buy. People may be slow to respond, but they usually get there in the end.
2) With no Washington Treaty does Britain retain the 10 Year rule after the Chanak Crisis with Turkey. This toggle gives a plausible reason to accelerate British RN and RAF build-ups.
Interesting point about the 10 Year Rule and Chanak, both of which I've only become aware of through reading up on the subject. Personally I think the lack of a Washington Treaty changes the game far more than an essentially ephemeral crisis in a decaying power.
3) Do Commonwealth members drop their objections to renewing the Anglo-British Naval Treaty. In the absence of Washington, London would have a much greater incentive to conclude a bilateral treaty. If the treaty was renewed, then Britain and the Commonwealth might well stand aside from the a US/Japanese war in the Pacific.
That's a good point, though does Japan really want war with the US, or just to cover its flanks while it makes a grab for the oil in the Dutch East Indies? A thrust south leaves the Phillipines a threat on the sea lines between Indonesia and Japan, but also puts the British and French on their other flank in Malaya and Indochina. Britain's traditional affection for the underdog will put any alliance under immediate strain if Japan attacks the Dutch. And if the British are a threat, then Hong Kong is a knife at Japan's throat. By an accident of geography, the one thing Japan wants most is held by the weakest colonial power, but is located such that she has to contemplate war with all if she wants war with one.
4) China is a fascinating "what if". Maybe Manchuko is accelerated a few years and game gets a much deeper focus on Japan with Manchurian auxiliaries trying to conquer the balance of China or even a coup where China goes over to the Japanese side (that's a big coding task since you have to create the Chinese as faux Japanese units). "Asia for the Asians" had a real resonance for some former colonies in WW2 where the Japanese occupation wasn't so brutal to drive the locals onto the Allied side.
Japan doesn't seem to have had the diplomatic subtlety to be able to sell that view widely in WWII, I don't see them doing any better in the 20s. I think China for Japan is precisely the same kind of mistake that Russia was for Napoleon and Hitler. Better to play the waiting game and have it fall to you piecemeal. That's how Britain conquered India, after all.
5) Is the conflict likely enough that at least some of the merchant marine on both sides has already gotten their armament before the fighting starts?
Everyone planned for it, but there seem to be few enough cases where it was pulled off. A more deliberate approach to readying for war might allow you to do it, but risks sending messages to your opponent as to what is coming.
Looking at the Never-Weres; no Washington gets you the Cherry Trees: British, American and Japanese, and the Tillmans may come as a reaction to the British and Japanese ships, but for the RN to have the last three Admiral class we need something earlier. Britain stopped the Admirals because Germany stopped the Mackensens, but if Germany keeps on with the Mackensens and the Ersatz Yorcks, so that we can justify the Admirals, then what else does that indicate about the way the Great War played out?
Another interesting point of departure is to assume no Kanto earthquake, which puts the Japanese on a much sounder financial footing, as well as likely saving a bunch of new construction in the yards. WPO assumes Amagi as a BC in the battleship-heavy scenarios, in which case she would probably have been in the water rather than the yard when Kanto struck, but if Amagi was off the slip then likely some other hull in the 8+8 programme would have been there to be affected instead.