What if the USA had been conquered by a theocratic Imperial Japan prior to World War II?

The title pretty much says it all. Let's assume sometime between Japan's conquest of Qing China in the mid-19th century and its Imperialist expansion into the Americas in the late 19th century the USA was conquered by Imperial Japan. What would the world look like if the USA was a vassal state for Imperial Japan prior to World War II. How would Japan run the continent? Would it take the same route it did with China and Korea or another route entirely?