Final answer:
The principle of separation of powers is likely the most fundamental for the successful operation of the American government, as it establishes the foundation for checks and balances, supports federalism, and ensures that governance is in accordance with popular sovereignty.
Step-by-step explanation:
In assessing which idea from the US Constitution is fundamental for the American government to work successfully, it's important to understand the individual concepts:
- Separation of powers ensures that the government is divided into three branches—legislative, executive, and judicial—each with distinct responsibilities and powers.
- Checks and balances prevents any one branch from becoming too powerful by providing each the means to restrain the actions of the others.
- Federalism is a system of government in which entities such as states or provinces share power with a national government.
- Popular sovereignty holds that the government's authority comes from the consent of the governed.
While all these principles are important, separation of powers may be considered the most crucial, as it underpins the functionality of the checks and balances system and is intrinsic to the operation of federalism and the fulfillment of popular sovereignty. The proper functioning of each branch is essential to ensure that no single entity gains unchecked power, thus maintaining a balance essential for a democratic process.