Constitution 101 the federal system

The Constitution which is the plan of the federal government of the United Stated is not a central government like a monarchy it is a federal system with power shared between the people the cities and the states and the fed  with most power in the hands of the people.
Just as the people gave only as much power to the towns and cities as necessity required, so the town and cities only gave the states as much power as required...The states only give the Federal government as much power as required and even that LIMITED power was held within a system of checks and balances. The goal was to ensure that WE THE PEOPLE remained free and in charge of out own lives 

federal

/ˈfɛdərəl/

1.

of or relating to a form of government or a country in which power is dividedbetween one central and several regional governments

2.

of or relating to a treaty between provinces, states, etc, that establishes apolitical unit in which power is so divided.

So under a federal system the power of the central government is both limited and controlled 

As the people gave only those limited  powers to the city or town that necessity required, the cities and towns gave only those LIMITED powers to the States that necessity required; So  the States give only those Limited power to the Federal government that necessity required. Basely the Federal government was given the power to deal with foreign nations; so all America would speak with one voice and to settle peacefully disputes between states and even then a system of checks and balances was built in. 

The whole idea is to insure that WE THE PEOPLE  remain free and in control of our own lives.