In late 1921, the USA, Britain and Japan had good reason to conclude a naval limitation treaty as the USN could not get money from Congress and the economies of Britain and Japan could not support an unlimited naval race. The problem was getting Japan to agree the 60% ratio that was desired by the other powers. Historically, America was able to read Japanese codes and could thus negotiate successfully (well in the short term!).
What if Japan had better codes (or perhaps even better realized that the US were reading their codes and could send misleading information) and also had a very far sighted government. Thus the Japanese declares that they will not accept less than 70% unless the treaty is accompanied by a commercial treaty by which the parties agree not to raise tariffs against each other. The logic would be that Japan must either be able to export to the USA and the British Empire or to control China.
I suspect that all the parties would be happy with this in 1921-2 and thus we can assume the Naval Treaty is signed as OTL and the Commercial Treaty simultaneously. What are the consequences?
What if Japan had better codes (or perhaps even better realized that the US were reading their codes and could send misleading information) and also had a very far sighted government. Thus the Japanese declares that they will not accept less than 70% unless the treaty is accompanied by a commercial treaty by which the parties agree not to raise tariffs against each other. The logic would be that Japan must either be able to export to the USA and the British Empire or to control China.
I suspect that all the parties would be happy with this in 1921-2 and thus we can assume the Naval Treaty is signed as OTL and the Commercial Treaty simultaneously. What are the consequences?