One of the guiding principles of the U.S. Government is federalism. Federalism is the division of power between the federal (national) government and the state governments. Reserved powers are those that were kept for state governments. Laws that reflect reserved powers can vary from state to state and often reflect the unique needs and wants of that state's citizens. An example of a reserved power for the states is the power to issue marriage licenses. There are also powers that have been delegated to the federal government. These are powers that relate to the wants and needs of the nation as a whole and provide a sense of uniformity and security for the nation. There are also instances where the federal and state governments can share powers. These "concurrent" powers can be seen with things like enforcing laws or providing for the welfare of citizens.