The country was originally chartered as a Federation with the Federal Government having practically NO power. That has changed significantly over the years.

Our civil war was fought under the banner of 'states rights' but it was whether or not they had the right to slavery that was the key. Since that war, and particularly since WWII the individual states have had less and less independent rights.

The system actually works, after a fashion. Not particularly smoothly, or without strife and angst, but it usually works. In the last 250 years the balance between has been adjusted many times.