Chief Justice William Howard Taft, writing for the majority in Ex Parte Grossman, 267 U.S. 87 (1925):
To afford a remedy, it has always been thought essential in popular governments, as well as in monarchies, to vest in some other authority than the courts power to ameliorate or avoid particular criminal judgments. It is a check entrusted to the executive for special cases. To exercise it to the extent of destroying the deterrent effect of judicial punishment would be to pervert it; but whoever is to make it useful must have full discretion to exercise it. Our Constitution confers this discretion on the highest officer in the nation in confidence that he will not abuse it.
