Martial Law, a term often confounded with military law, but in fact quite distinct from it. Military law, besides some customary law, consists chiefly of the articles of Avar; that is to say, of the code enacted by the supreme legislative authority for the government of the army and navy. It embraces, also, the body of rules and regulations which are prescribed from time to time by competent military authority, for the preservation of the general discipline and order. Military law does not supersede the general municipal law; it is rather a branch of it, more limited in the range of its application than the admiralty or the chancery law, for example, yet having a like authority with them. In this country, unlike some of the states of continental Europe, the application of military law to the soldier is not exclusive of, but coordinate with, the general civil law. Every soldier, as a citizen, is subject to the common law of the land; but as a soldier ho is amenable to the military law. The special tribunals which administer this law are named courts martial, and hence perhaps has arisen in part the confusion of the military law with the law martial. (See Court Martial.) Martial law, says Blackstone, is in fact no law at all.
Smith, in his "English Republic," says: "Martial law is the law of Avar, that depends on the just but arbitrary power and pleasure of the king. For, though he doth not make any laws but by common consent in parliament, yet in time of Avar, by reason of the necessity of it, to guard against dangers that often arise, he useth absolute power; so that his Avord is a law." However opposed to other authorities, this expresses what is distinctively meant both in England and in this country by martial law. When in time of extreme peril to the state, either from without or from within, the general safety cannot be trusted to the ordinary administration, or the public Avelfare demands the adoption and execution of extraordinary measures, it may become necessary to declare the existence of martial law. This is, indeed, no law at all in its ordinary sense; it is in fact the abrogation of it. That which is done under martial law has not an immediate constitutional or legislate sanction, as the military or the statute law has. It proceeds directly from the military power, which has now become supreme.
The supreme court of the United States has held that a state legislature may proclaim its existence whenever the public safety demands it; and the constitution, by implication at least, also permits its proclamation by that clause which provides that the privileges of the writ of haheas corpus shall not be suspended, unless when, in cases of rebellion or invasion, it is essential to the general welfare. The right to judge whether the exigency has arisen belongs, it seems, exclusively to congress. So in England martial law and its incident, the suspension of the writ of haheas corpus, require the authority of parliamentary acts to give them a constitutional existence. The supreme court of the United States also held in Milligan's case (4 Wallace, 2), that martial law could not be permitted, even during the existence of a civil war, to displace the ordinary administration of law in a state not invaded and not engaged in rebellion, and where the courts were open and in the proper and unobstructed exercise of their functions; and that the guaranty of jury trial in the constitution would make void, all trials and sentences by military tribunals in such states of citizens not in military or naval service.
And neither the president, nor congress, nor the judiciary, it was held, could take from the citizen the benefit of such guaranty under the circumstances stated.