Which of the following is a power exclusive to the federal government?

Regulating interstate commerce is a power that is exclusive to the federal government and is granted by the Commerce Clause of the Constitution. This clause provides Congress with the authority to regulate trade and commerce between states, ensuring a uniform system of commerce that promotes economic efficiency and prevents states from engaging in trade disputes or discriminatory practices against each other.

The other options listed are powers typically reserved to the states. Establishing schools is primarily a state responsibility as education policy can vary greatly depending on local needs and priorities. Issuing marriage licenses is also managed by states, allowing them to set their own regulations and requirements. Conducting elections is another power that lies predominantly with the states, as they determine the procedures for running elections within their jurisdiction. Thus, regulating interstate commerce stands out as a specifically federal power, emphasizing the distinct roles assigned to each level of government.