A more thorough explanation:

The dual-prosecution rule is a legal principle that allows both the federal government and a state government to prosecute a defendant for the same offense. This is because both governments are considered separate and distinct entities.

For example, if a person is accused of committing a crime that violates both state and federal laws, they may be prosecuted by both the state and federal government. This means that the defendant could face two separate trials and potentially receive two separate punishments.

The dual-prosecution rule is based on the dual-sovereignty doctrine, which recognizes that both the federal government and state governments have their own separate powers and jurisdictions. This principle allows for the efficient enforcement of both federal and state laws, and ensures that defendants are held accountable for their actions at both levels of government.