by Eric Rauchway

point belowEx parte Milliganon a reasonable readingMilliganforcible terms in which the Court wrote
The proposition is this: that in a time of war the commander of an armed force (if in his opinion the exigencies of the country demand it, and of which he is to judge), has the power, within the lines of his military district, to suspend all civil rights and their remedies, and subject citizens as well as soldiers to the rule of his will; and in the exercise of his lawful authority cannot be restrained, except by his superior officer or the President of the United States.
If this position is sound to the extent claimed, then when war exists, foreign or domestic, and the country is subdivided into military departments for mere convenience, the commander of one of them can, if he chooses, within his limits, on the plea of necessity, with the approval of the Executive, substitute military force for and to the exclusion of the laws, and punish all persons, as he thinks right and proper, without fixed or certain rules.
The statement of this proposition shows its importance; for, if true, republican government is a failure, and there is an end of liberty regulated by law....
It will be borne in mind that this is not a question of the power to proclaim martial law, when war exists in a community and the courts and civil authorities are overthrown. Nor is it a question what rule a military commander, at the head of his army, can impose on states in rebellion to cripple their resources and quell the insurrection. The jurisdiction claimed is much more extensive. The necessities of the service, during the late Rebellion, required that the loyal states should be placed within the limits of certain military districts and commanders appointed in them; and, it is urged, that this, in a military sense, constituted them the theater of military operations; and, as in this case, Indiana had been and was again threatened with invasion by the enemy, the occasion was furnished to establish martial law. The conclusion does not follow from the premises. If armies were collected in Indiana, they were to be employed in another locality, where the laws were obstructed and the national authority disputed. On her soil there was no hostile foot; if once invaded, that invasion was at an end, and with it all pretext for martial law. Martial law cannot arise from a threatened invasion. The necessity must be actual and present; the invasion real, such as effectually closes the courts and deposes the civil administration.