____________ is a system of government that creates two relatively autonomous levels of government, each possessing authority granted to them by the national constitution. Systems like the one in the United States are different from unitary systems, which concentrate authority in the national government, and from confederations, which concentrate authority in subnational governments. The U.S. Constitution allocates powers to the states and federal government, structures the relationship between these two levels of government, and guides state-to-state relationships.