why does the president have power to pardon
Pardon In the United States, the pardon power for federal crimes is granted to the President of the United States under Article II, Section 2 of the United States Constitution which states that the President "shall have power to grant reprieves and pardons for offenses against the United States, except in cases of impeachment". The U.S. Supreme Court has interpreted this language to include the power to grant pardons, conditional pardons, commutations of sentence, conditional commutations of sentence, remissions of fines and forfeitures, respites, and amnesties.[27]
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.