The Founding Fathers built the U.S. Constitution on a foundation known as federalism.  In the minds of the Federalists, federalism allowed states to be unified under one nation, but still gave them autonomy to meet the needs of the citizens they governed.  This flexibility has allowed cooperation between the states and the national government, but also led to conflicts because the U.S. Constitution does not always clearly defined what authority is granted to the states versus the federal government. How does the Constitution use federalism to achieve objectives of government, such as promoting the general welfare, protecting and promoting the blessing of liberty and ensuring domestic tranquilty?