<P> In 1980, after the courts had dismissed their appeals, the Home Secretary, William Whitelaw, used the Royal prerogative of mercy to free David Cooper and Michael McMahon from their imprisonment, both having been convicted of murder on poor evidence . </P> <P> Under the Act of Settlement, a pardon cannot prevent a person from being impeached by Parliament, but a pardon may commute any penalties imposed for the conviction . In England and Wales no person may be pardoned for an offence under Section 11 of the Habeas Corpus Act 1679 (unlawfully transporting prisoners out of England and Wales). </P> <P> 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 . </P> <P> Almost all federal pardon petitions are addressed to the President, who grants or denies the request . In rare cases, the President will, of his own accord, issue a pardon . Typically, applications for pardons are referred for review and non-binding recommendation by the Office of the Pardon Attorney, an official of the United States Department of Justice . The percentage of pardons and reprieves granted varies from administration to administration; however, fewer pardons have been granted since World War II . </P>

Why does the president have power to pardon
find me the text answering this question