Which power is exclusively reserved for the federal government?

The power to declare war is exclusively reserved for the federal government, specifically Congress. This authority is outlined in the U.S. Constitution, which grants Congress the power to declare war and manage conflicts involving the nation. This ensures that the decision to engage in military action is made at a national level, reflecting a unified stance rather than varying decisions at the state level.

In contrast, regulating trade can involve both state and federal governments, as both entities have roles in trade regulation within their respective jurisdictions. Conducting elections is primarily a state function, as states administer their own election processes. Similarly, the establishment of local governments is also a state responsibility, as states have the authority to create and manage local government structures. This distinction highlights the unique nature of the power to declare war, emphasizing its significance in federal governance and national unity.