Three parts. They are the Executive, (President and about 5,000,000 workers) Legislative (Senate and House of Representatives) and Judicial (Supreme Court and lower Courts).
The president of the United States is authorized under the Constitution to nominate persons to executive and judicial posts with the Senate's recommendation and approval.
The Senate has influence on the executive and judicial branches, which is a vital check on the constitutional authority.
The Supreme Court is made up of eight associated justices and the Chief Justice of the United States.
The president has the authority to appoint the justices, and these nominations are made with the Legislature's advice and approval.
