the ability of congress to override a presidential veto
Veto If the Congress overrides the veto by a two-thirds vote in each house, it becomes law without the President's signature. Otherwise, the bill fails to become law unless it is presented to the President again and the President chooses to sign it.[12] Historically, the Congress overrides the Presidential veto 7% of the time.[13]
Powers of the President of the United States The Constitution explicitly assigned the president the power to sign or veto legislation, command the armed forces, ask for the written opinion of their Cabinet, convene or adjourn Congress, grant reprieves and pardons, and receive ambassadors. The president may make treaties which need to be ratified by two-thirds of the Senate. The president may also appoint Article III judges and some officers with the advice and consent of the U.S. Senate. In the condition of a Senate recess, the president may make a temporary appointment.