Answer:
The principle of Federalism is most reflected in the US Government & the Constitution's limits on the Federal Government's powers and the reservation of powers for the States. This is set forth clearly in the 10th amendment.
Federalism is evident throughout Government. An example of the US Department of Education. Education is a power reserved to the States and so the US Department of Education funds projects and ensures equity but the power to set curriculums is done by the States.
