The American-Japanese coalition problem

The counterfactual requires a political upheaval strong enough to silence figures such as Admiral Ernest King, who might dislike Britain but would oppose an unready war. The U.S. Navy, like Japan's forces, still needs nearly three years of building, research, and development before it resembles its later Pacific War strength. The Royal Navy is not fully ready either, but it has greater mass and has consistently favored numbers. The premise creates a formidable coalition whose two members remain unprepared for an immediate conflict.