Which principle of government ensures that no single branch becomes too powerful?

The principle that ensures no single branch of government becomes too powerful is checks and balances. This system is designed to maintain a separation of powers among the three branches of government: the legislative, the executive, and the judicial. Each branch has distinct responsibilities and powers, and they can limit or check the actions of the others. For instance, while the legislative branch makes laws, the executive has the power to veto those laws, and the judicial branch can declare laws or executive actions unconstitutional. This interdependence means that power is not concentrated in any one branch, thus protecting against tyranny and abuse of power.

The other principles listed, such as federalism, pertain to the division of power between national and state governments, while executive privilege covers the right of the president to withhold information. The rule of law emphasizes that everyone, including government officials, must follow the law. While these concepts are important in the framework of governance, checks and balances specifically address the concern of power concentration among the branches.