Final answer:
The American government is a democratic presidential republic characterized by elected leadership, federalism, and a system of checks and balances. It is unique due to its combination of republican and democratic principles, and the division of power between national and state governments.
Step-by-step explanation:
The distinguishing features of the American form of government are particularly notable when compared with other governmental systems. The United States is defined as a democratic presidential republic, meaning it has a form of government where the president is the head of state, elected by the people, and holds significant power.
Three basic criteria that determine a nation's form of government include who holds power, how leadership positions are obtained, and how authority is maintained. In the U.S., power is held by elected representatives (including the president), positions of leadership are obtained through democratic elections, and authority is maintained through a system of checks and balances among the separate branches of government.
The U.S. government operates on federalism, dividing power between national and state governments. This is distinct from unitary states where a central government holds the majority of the power. Moreover, the U.S. Constitution incorporates principles of both republican and democratic forms of government by allowing citizens to elect representatives (republican principle) and by ensuring those representatives are accountable to the people (democratic principle).