I suppose that the president is the King/Queen in all but name

In the Japanese and English political systems they were okay with hypocrisy that's why systems so just the Prime minister and Shogun

Could fuction and create political stability also the American president was never supposed to be a powerful figure

But the USA needed to become a mature state which meant the creation of a functional central government

Over the original idea that it would be the States that would be the ultimate authority within the United States of America

You may find the book Asian power and politics an very interesting read