Could Britain keep the United States out of the war?

Could Britain prevent the United States from entering an Anglo-Japanese war?

No. American entry would be hard to refuse and would add bases, battle-fleet strength, carriers, and a useful division between slow and fast forces.

Britain could not realistically reject a United States declaration of war without creating the absurd prospect of attacking a state that had joined its side. American bases and carriers would matter alongside the battle fleet itself. Slower American and Allied battleships could form a steadily advancing reserve, freeing faster ships for a separate striking force. That fast element might combine modernised Queen Elizabeths, Royal Navy battlecruisers, Dunkerques, Scharnhorsts, Ark Royal, and a Yorktown-class carrier. The arrangement is a counterfactual force concept that uses American depth to widen Allied operational choices.