All executive officers are under obligation to recognize and enforce the laws made by the legislative department within its proper sphere of action; and subordinate executive officers, such as the secretaries or heads of departments, may be compelled by proceedings in court to perform duties which are purely ministerial, and may be held liable in damages for injuries suffered by private persons by reason of the failure to discharge legal duties affecting the rights of such persons. If, however, the duty imposed upon the inferior executive officer is one involving the exercise of discretion - and many duties thus imposed are of this character - then, while he may be required to act, he cannot be controlled in the exercise of the discretion imposed upon him by law, nor can he be held liable in damages, if his discretion is exercised in good faith and on a proper occasion.

As to the chief executive, it has generally been considered that the independence of the executive department, while it does not exempt him from the obligation to respect the law, does require that he be free from interference on the part of the judicial department. Thus, courts cannot compel the execution of a grant of land by the executive, although it is required by law; nor can they enforce his attendance in court or before a grand jury as a witness (State v. Stone). But on these questions there is difference of opinion among the courts, some being inclined to insist that, as no officer is too high to be amenable to law, the courts can compel the observance of law by the chief executive as well as by any other person; whilst others insist that it would be an interference on the part of the judiciary with executive independence if the chief executive were coerced as to his official action by the orders of a court, or prevented from performing his high executive functions by imprisonment. However, any clashing of authority between the executive and the judiciary has usually been avoided by the exercise of wise forbearance and mutual discretion. For instance, the president or a governor will not refuse to give testimony in a proper case pending in court in which his evidence is sought, though he might insist that he cannot be compelled to do so; and the courts, on the other hand, will not issue compulsory process against such an officer, though they may request his presence for the giving of testimony on a proper occasion. It is always to be borne in mind that the executive is vested, under the constitution, with independent power and discretion, and that he cannot by any legal process be compelled to submit to inquisition on the part of the courts as to matters solely within the proper scope of the discharge of his executive duties, nor dictated to with reference to such matters by the courts, or even the legislature.

Fortunately the occasion has seldom arisen for considering how far the courts may proceed against an individual who is vested with supreme executive authority, for acts or conduct not official in character. He may be sued as any other individual, and his private property may be taken to satisfy a judgment. Whether he could be arrested, tried, and punished by imprisonment, while holding his official position, for crimes committed by him as an individual, and not in connection with his official duty, may well be left unsettled until some occasion arises for the determination of the question. No such difficulty exists with reference to subordinate executive officers. They are in every respect fully amenable to the judiciary. No commands of superior officials will excuse them for violations of law, nor will any plea of interference with the performance of official duty be sufficient to exempt them from obeying the process of the courts. It may well be assumed that necessary executive functions can be otherwise discharged, although they as individuals are incapacitated from performing them (Marbury v. Madison).

The chief executive and other officers are subject to removal from office on impeachment by the legislative department for crimes and misconduct while in office, and this power of supervision on the part of the legislative department over the executive has sometimes been suggested as evidence of the subordination of the executive to the power of the legislature. But in discharging the power of impeachment and trying the officer for the" crime or misconduct alleged against him, the branches of the legislative department act rather in a judicial than a legislative capacity. The court of impeachment, consisting of the senate in the case of a federal officer, and usually of the higher branch of the state legislature in the case of a state officer, does not act as a legislative body, but proceeds in accordance with the provisions of the federal or state constitution, as the case may be, to determine whether the officer charged has been guilty of the crime or misconduct alleged, and whether, in consequence thereof, he shall be removed from office. (See below, § 28.) In this there is no infringement by the legislative department of executive independence.

It has already been pointed out (see above, § 7) that there are many political questions and questions affecting international relations, as to which the action of the executive department is conclusive, and cannot be reviewed or passed upon by the courts.