Maybe I should put it this way: US already reached its peak status, and it's very difficult to even find a way or area to "grow". In 1920s, although US became a

Maybe I should put it this way: US already reached its peak status, and it's very difficult to even find a way or area to "grow". In 1920s, although US became an economic super power, there were still plenty of room to grow in the area of international political system.