The interwar Anglo-Japanese Alliance outlives a reduced US Navy

What if the US Senate sharply reduced the navy after the First World War, no naval conference followed, and the Anglo-Japanese Alliance continued?

Japan modernizes without an urgent American arms race, supports British commitments, and may turn its strategic attention toward the Soviet Union.

A reduced American naval programme removes much of the pressure for a rapid Japanese fleet expansion. Japan could modernise and complete the Eight-Eight programme gradually while retaining its British alliance. Without a Washington conference and with the United States withdrawing from international commitments, Britain would have less reason to abandon that relationship. Japan could send Britain whatever forces it could spare without undermining home defence, including help against Italy in the Mediterranean. A Soviet invasion of eastern Poland might also give Japan a reason to renew attacks on the Soviet Union.