During the US Civil War period the Confederate States of America was just that - basically an alliance of states with a weak central government. But there are also confederacies of nations as well such as what occurred with the former Soviet Union.
Federal
unitary
It doesn't quite work that way. The States and their people ARE the government, and they have allowed the Federal government to do a very few things like regulate sales of items between and among the States, provide a military to protect all of the States, and to mint money.
Federal System
federal
The national government and the state government.
The system of government which guarantees that each state has representation at the national level is a republic. America has a republic government.
Federal
federal
federal
The answer is.....Separation Of Powers
The national government, not the state governments.
Having two sovereigns, the national government and the state governments.
federalism
unitary
A national government and state governments
Federalism. The system that divides power between the national government and the state government is called the "Federal System."