The Attorney-General objected to the leave asked for, upon the ground that no bill which makes a President a defendant, and seeks an injunction against him to restrain the performance of his duties as President, should be allowed to be filed in this court. . . .
The single point which requires consideration is this: Can the President be restrained by injunction from carrying into effect an act of Congress alleged to be unconstitutional?
It is assumed by the counsel for the State of Mississippi, that the President, in the execution of the Reconstruction Acts, is required to perform a mere ministerial duty. In this assumption there is, we think, a confounding of the terms ministerial and executive, which are by no means equivalent in import.
A ministerial duty, the performance of which may, in proper cases, be required of the head of a department, by judicial process, is one in respect to which nothing is left to discretion. It is a simple, definite duty, arising under conditions admitted or proved to exist, and imposed by law.
The case of Marbury v. Madison . . . furnishes an illustration. A citizen had been nominated, confirmed, and appointed a justice of the peace for the District of Columbia, and his commission had been made out, signed, and sealed. Nothing remained to be done except delivery, and the duty of delivery was imposed by law on the Secretary of State. It was held that the performance of this duty might be enforced by mandamus issuing from a court having jurisdiction.
So, in the case of Kendall, Postmaster-General, v. Stockton & Stokes, 12 Peters, 527, an act of Congress had directed the Postmaster-General to credit Stockton & Stokes with such sums as the Solicitor of the Treasury should find due to them; and that officer refused to credit them with certain sums, so found due. It was held that the crediting of this money was a mere ministerial duty, the performance of which might be judicially enforced.
In each of these cases nothing was left to discretion. There was no room for the exercise of judgment. The law required the performance of a single specific act; and that performance, it was held, might be required by mandamus.
Very different is the duty of the President in the exercise of the power to see that the laws are faithfully executed, and among these laws the acts named in the bill. By the first of these acts he is required to assign generals to command in the several military districts, and to detail sufficient military force to enable such officers to discharge their duties under the law. By the supplementary act, other duties are imposed on the several commanding generals, and these duties must necessarily be performed under the supervision of the President as commander-in-chief. The duty thus imposed on the President is in no just sense ministerial. It is purely executive and political.
An attempt on the part of the judicial department of the government to enforce the performance of such duties by the President might be justly characterized, in the language of Chief Justice Marshall, as "an absurd and excessive extravagance."
It is true that in the instance before us the interposition of the court is not sought to enforce action by the Executive under constitutional legislation, but to restrain such action under legislation alleged to be unconstitutional. But we are unable to perceive that this circumstance takes the case out of the general principles which forbid judicial interference with the exercise of Executive discretion.
It was admitted in the argument that the application now made to us is with-