There is a government unique to the United States.

Representative

It is many things. Appropriate titles are Constitutional Democracy, Representative Democracy, or a Republic.

There are three branches of government

Executive with the President

Legislative with Congress

Judicial with the Judicial

System

They all work together with a system of checks and balances, so one branch doesn't have too much power.

The Executive Branch can keep the Legislative Branch in check by vetoing their laws

The Legislative Branch can keep the Executive Branch in check by rejecting their Judicial nominations and overriding their vetoes.

The Executive Branch can keep the Judicial Branch in check by nominating the federal judges.

The Judicial Branch can keep the Exective Branch in check by declaring acts of the executive unconstitutional.

The Legislative Branch can keep the Judicial Branch in check by appointing or rejecting judicial nominations.

The Judicial Branch can keep the Legislative Branch in check by declaring laws unconstitutional.