An Axis America would face an Allied two-ocean strategy

What if the United States joined the Axis and Japan joined the Allies?

America would face a two-ocean war and internal political risk, while Britain lost US supplies but gained Japan as a powerful Pacific partner.

The scenario requires a strong American fascist movement to take power, which could also encourage Spain to join the Axis. Britain would lose American supplies and high-octane aviation fuel, forcing more traffic toward African and imperial routes while facing German and American submarines. The United States could not concentrate freely in the Atlantic because an Allied Japan would threaten the Pacific and punish whichever ocean Washington neglected. Britain and Japan could exploit that division, while Canada and internal American resistance might turn federal consolidation into a civil war. Logistics, geography, and political control would determine the conflict before a simple comparison of battle fleets became useful.