Which of the following is a power reserved for the states under the Constitution?

The power to provide protection through police forces is reserved for the states under the Constitution. This reflects the principle of federalism, where certain powers are explicitly delegated to the federal government while others are reserved for state governments.

State governments are responsible for maintaining law and order, which includes establishing and operating police departments. This function is crucial for ensuring public safety and enforcing state laws, making it a core responsibility of state governance.

In contrast, printing money, creating an army, and making treaties are powers that are exclusively granted to the federal government. Only the federal government can manage the currency and national defense, as well as engage in foreign relations, ensuring that these critical functions remain consistent across the nation. This division of powers is foundational to the structure of the U.S. government.