ON JUST OR SOLEMN WAR ACCORDING TO THE LAW OF NATIONS ON DECLARATIONS OF WAR. Solemn war, according to the Law of Nations between different states--A people, though engaged in unjust war, to be distinguished from pirates and robbers--Change in the condition of belligerents--Formal war can be made by the Sovereign power alone--Declaration of war--The Law of Nature, Law of Nations, respecting the same--Declaration, conditional, absolute--Forms of declaration introduced by the civil law--War declared against a Sovereign includes his subjects, and allies--The reason why allies are included--Declarations, why necessary to establish certain effects--Whether actual warfare immediately follows a declaration, considered--Whether the violation of an Ambassador's rights to be a just ground of war. I. In the first book of this treatise it was observed, that according to the best writers, a war is defined to be just, not on account of the CAUSES solely, in which it originates, nor on account of the MAGNITUDE of its objects, but from certain, peculiar, effects of right, with which it is attended. But to what kind of war such an appellation most duly belongs will be best understood by considering the definition, which the Roman Lawyers have given of a PUBLIC or NATIONAL enemy. "Those, _says Pomponius_, are PUBLIC and LAWFUL ENEMIES, with whose STATE our own is engaged in war: but enemies of every other description, come under the denomination of pirates and robbers." With that opinion Ulpian entirely accords, making an additional observation, that "if any one be taken by robbers, as he is not a lawful prisoner of war, he cannot claim of his own state the right of postliminium. But if he be taken prisoner by a public enemy of the state, being considered as a prisoner of war, he is entitled by the right of postliminium to be restored to his former condition." These opinions are supported by that of Paulus, who maintains, that persons captured by pirates still continue free, that is, are not to be considered as prisoners, for whom an exchange may be demanded. So that by the opinion of the Roman Lawyers it is evident, that no war is considered to be lawful, regular, and formal, except that which is begun and carried on by the sovereign power of each country. Cicero, in his fourth Philippic, describes "a public and authorised enemy to be the person, who possesses the civil and military powers of the state, who can command the treasury, and the services of the people in support of his measures, and who, as occasions offer, has power to conclude treaties of peace and amity."