What major Political institution the Bureaucracy,the Congress, the Judiciary, or the Presidency is the most Powerful actor in contemporary American Politics?

What major Political institution the Bureaucracy,the Congress, the Judiciary, or the Presidency is the most Powerful actor in contemporary American Politics? Site a contemporary example to justify your assertion. Should this actor be so powerful, or would we be better off if we were to adopt institutional changes that redistributed the power balance among these political institutions or specifically to one of the institutions?