Why Britain and America divided naval theaters in World War II

Could the Royal Navy deploy farther into the Pacific early in the Second World War?

It could reinforce from the Eastern Fleet, but Allied basing and competing threats made it sensible for Britain to lead in the Atlantic, Mediterranean, and Indian Ocean while America led in the Pacific.

Britain maintained an Eastern Fleet in the Indian Ocean that could move farther east in an emergency. German and Italian demands absorbed much of the Royal Navy, however, so the Anglo-American division of effort matched each navy's existing bases, concentration, and operational reach. American ships and methods had been developed for a trans-Pacific advance supported across great stretches of open water. British plans instead relied on a chain of imperial bases and an advance from Singapore through the South China Sea toward Hong Kong and Weihaiwei. Each navy's damage tolerance, training, and logistics followed those different routes. The broader lesson is that a doctrine which is effective for one basing system can ruin a force whose ships and support network were built for another.