Why a different war produces a different naval treaty

Would the United States simply force an Anglo-German-Japanese alliance to dissolve at a Washington-style naval conference?

Not necessarily, because the historical treaty depended on the actual First World War's economic and strategic outcome, which this counterfactual removes.

The viewer assumes that the United States would still demand the end of an Anglo-German-Japanese coalition at Washington. That assumption imports the historical 1920s settlement into a world where a shorter European war left different winners, finances, and naval incentives. Without the same wartime debts and Anglo-German naval rivalry, neither the conference nor its bargaining power would necessarily take the familiar form. The coalition might instead persist, with the United States choosing between joining it and attempting an expensive confrontation without obvious partners.