In order to ensure that the people were sufficiently protected from a tyrannous government, the framers of the US Constitution introduced institutional precautions and individual protections. These are important aspects of US government operations that help explain the sometimes difficult relations between the various arms of government and their relationship with the people.

Legislature (Congress) Executive (President) Judiciary (Supreme Court)
Checks the Executive:
Controls the scope and powers of executive departments and agencies.
Has the power to approve or reject the executive’s federal budget request.
Can impeach and try executive officials, including the president if he is deemed to have done wrong.
Can override a presidential veto on a bill that has passed Congress with a two-thirds majority in each chamber.
Senate approves treaties with other countries and all key departmental appointments as well as US ambassadors made by the president.
Checks the Legislature:
Can veto legislation passed by Congress.
Can recommend legislation to Congress in order to support their policy agenda.
Can pardon convicted individuals and grant amnesty to those likely to be prosecuted for federal crimes.
Can call special sessions of Congress to resolve unfinished or new business.
Checks the Legislature:
Through judicial review, the courts can declare laws unconstitutional.
Checks the Judiciary:
Senate approves all federal judges, including Supreme Court Justices appointed by the president.
Can impeach and try judges if they are deemed to have done wrong.
Can create and abolish court systems, as well as alter the size of the Supreme Court.
Can restrict the jurisdiction of courts to hear certain cases.
Checks the Judiciary:
Appoints all federal judges, including Supreme Court Justices.
Checks the Executive:
Presides over impeachment trial of executive officials, including the president.
Can declare a presidential action unconstitutional and require it to be changed.