Answer:
Federalism
Step-by-step explanation:
A Federation is a set of states that are independent of each other, which have their own law (state constitutions) but which together adopt a central government to resolve national or foreign issues. Thus, the states of the Federation draw their constitution for their territory, with the necessary specificities while the National Government takes care of national affairs, which are what all states have in common.
The US is a Federation. States are independent to establish their laws, but the Central Government takes care of national issues and the country's representation abroad.