National, state, and shared powers — plus unitary and confederal systems.
Three ways to organize a country
In a unitary system, almost all power sits in the national government. Local governments exist only because the center allows them. The United Kingdom is often used as the classroom example.
In a confederal system, independent states hold the real power and the central government is weak. The Articles of Confederation were confederal. The states were the bosses.
In a federal system, power is divided and shared between a national government and state governments. Both get their authority from the people through a constitution. The United States uses federalism.
Remember: Articles = confederal. Constitution = federal. One capital making every local decision = unitary.
Enumerated, reserved, concurrent, implied
Enumerated (delegated) powers are listed for the national government: declare war, coin money, make treaties, regulate interstate and foreign commerce, raise armies.
Reserved powers belong to the states or the people under the 10th Amendment. Examples: run public schools, issue driver’s licenses, run most elections, set most marriage and family law, create local governments.
Concurrent powers belong to both levels. Both can tax, borrow money, make laws, and set up courts. They cannot contradict the Constitution while they do it.
Implied powers come from the necessary and proper clause. McCulloch v. Maryland (1819) said Congress could create a national bank as a tool for its listed money powers, and Maryland could not tax that bank out of existence.
Denied powers and the 10th Amendment
Some powers are denied. Congress cannot pass an ex post facto law (punishing an act that was legal when it happened) or a bill of attainder (declaring someone guilty without a trial). The national government cannot take away habeas corpus except in extreme cases of rebellion or invasion.
The 10th Amendment is the federalism amendment: powers not given to the United States by the Constitution, and not forbidden to the states, are reserved to the states or the people.