The legislative department, in the exercise of its discretion, defines crimes and provides for their punishment. (See above, ch. x.) The courts determine whether a person charged with violation of the criminal law is guilty and prescribe his punishment. The executive department not only sustains the officers of the court in enforcing the punishment imposed, but exercises the independent function of suspending or annulling the punishment by reprieve or pardon. This independent power is in England recognized as one of the attributes of sovereignty, which, so far as the punishment for crime is concerned, has not been delegated to the judiciary, and under the federal and state constitutions .it is preserved as one of the functions of the executive department. State constitutions vest this power in the governor or an executive board, and the federal constitution expressly gives it to the president (Art. II, § 2, ¶ 1). It is to be noticed, however, that the power of the president to reprieve or pardon relates only to crimes committed against the federal government. He has no power to interfere with the execution of the laws of the states. And it is to be further noticed that the power of the president in this respect does not extend to punishment imposed on a public officer by impeachment.

The power of the president to pardon extends to every offence known to the federal law, and may be exercised by him at any time after its commission, either before legal proceedings are taken or during their pendency, or after conviction. It may be exercised by granting the pardon in a particular case, or by a general pardon or amnesty proclamation as to classes of persons who have been guilty of crime against the United States. Congress can neither limit the effect of a pardon nor exclude from the exercise of the pardoning power any class of offenders, and unconditional pardon not only relieves the offender from punishment, but extinguishes the consequences of his guilt, whether civil or criminal, so that after pardon the offender is free from the legal effects of his crime as fully as though no offence had been committed.

Congress, on the other hand, may attach as a condition or qualification to the holding of an office that the person to be appointed has not been guilty of- certain specified crimes, and the president's pardon will in such case not remove the disqualification. But in the cases of Cummings v. Missouri and In re Garland, it was held that neither by state constitution nor statute, nor by act of Congress, could a course of conduct which was not criminal at the time it was pursued, nor an offence for which a full pardon has been granted subsequently be made a ground of disqualification for holding office, as the effect would be to impose a penalty or an additional penalty by a subsequent statutory provision. Such legislation would be ex post facto in its nature and contrary to the express prohibitions of the federal constitution. (See above, § 59.)

A pardon may be granted upon conditions, and the immunity from punishment accorded thereby will continue only so long as the conditions imposed are complied with. A reprieve is not a conditional pardon, but a temporary suspension of punishment, and after the term of the reprieve has expired, punishment may be inflicted as though no reprieve had been granted.