The administrative power of the federal or a state government is necessarily vested in the executive department. Our system of government does not, however, recognize administrative law as superior to the civil law administered by the courts. Executive officers, even the highest, are subject to the law. Although the chief executive cannot be directly interfered with by the courts in the discharge of his duties (see above, § 25), he is liable, in both civil and criminal proceedings, for breach of the law in the same way as a private citizen; and subordinate executive officers may be directly controlled by the courts as to the discharge of their duties. It must be understood, however, that where a discretion is given to an executive officer he cannot be controlled by the courts in the exercise of his discretion, although he may be compelled to act where it is his duty to act, and prevented from acting where he has no right to do so (Marbury v. Madison).

In speaking of the division of power among the three departments of government, it is often said that the peculiar duty of the executive department is to enforce the laws made by the legislative department. By state constitutions it is usually provided that the executive shall take care that the laws are faithfully executed; and there is such a provision in the federal constitution (Art. II, § 3). It is also provided that the president shall take an oath to faithfully execute his office, and to the best of his ability preserve, protect, and defend the constitution of the United States (Const. Art. II, § 1, ¶ 7). The practical execution of the laws rests, however, more directly with the judiciary than with the executive department. It is for the courts to determine whether a law has been violated in a particular case, and what the redress or punishment shall be. If the authority of the court is resisted, then it is the function of the executive department to employ the power of the government, even the military power, if necessary, to uphold the authority of the courts and carry out their judgments; so that it is proper to say, in a general sense, that the ultimate power to enforce the laws is with the executive (In re Neagle).

The question has been mooted whether the president in the enforcement of the laws may take into account their constitutionality and disregard those which he believes to be unconstitutional. As to those acts which are purely executive and which are not subject to review by the courts, it is plain that the president must act on his own judgment and responsibility; but on the other hand, as to the interpretation of the constitution which has been announced by the judiciary in cases properly coming before that department, he should acquiesce in the decisions of the highest judicial tribunal. President Lincoln practically disregarded the Dred Scott decision in the policy of his administration with reference to slavery, and he was no doubt justified in doing so, for that decision had not and could not have any direct bearing on the duties of the executive department.

In the enforcement of the law it may become necessary for the president to use the military power, not only in securing obedience to the decisions of the courts, but also in preventing interference with the performance of governmental functions or the carrying on of governmental operations. For instance, if the transportation of the mails or the carrying on of interstate or foreign commerce is interfered with, he may undoubtedly employ such military force as is necessary to remove such interference. (See above, § 93.) The executive department is not bound to suspend the discharge of the duties with which it is vested until by judicial proceedings a remedy may be afforded. The president may use the military forces of the United States under such circumstances without being called upon by the legislature or governor of the State (In re Debs).