Right Of Search, the right of a belligerent to visit, by his lawfully commissioned cruisers, all private ships sailing on the high seas, and to examine their papers, and their cargoes if need be, in order to ascertain their destination and character. It is a familiar doctrine of international law that the ships of a state form a part of its domain, and that over them, as over its landed territory, the sovereignty of the state extends supreme and inviolable. In a time of general peace, these ships cannot be detained or boarded by the public ships of another power for the purpose of inquiry into their character or business, because such an act is an intrusion upon and in derogation of the sovereignty of the state whose ships are so visited. In time of war, however, the general consent of nations yields to the belligerents the privilege of visiting and searching ships professing to be neutral, in order that they may know that the neutral flag does not mask an enemy or cover contraband of war. So firmly is this rule or right established that there is no doubt or dispute about it among institutional writers, and it has never been successfully resisted in the practice of nations.
During the American revolutionary war, and in 1801, the Baltic powers declared that the flag of a state was a substitute for all documentary proof, and excluded the right of search. They armed themselves for the purpose of defending and maintaining this position, but they were soon compelled to abandon it, and since that time the usual war right has been considered incontrovertible. The question was once submitted in the English admiralty whether neutrals might not compel a belligerent to refrain from exercising his right by putting their ships under the convoy of a public ship of their country. It was adjudged that the belligerent was not bound to accept such a substitution, nor indeed in any respect to vary his right of personal visitation. It may be remarked in passing that two powers sometimes regulate or restrain by treaty the right of maritime search by ships of war. The English doctrines upon the war right of search have been generally admitted in this country, except as to the claim put forth by England of a right to search neutral vessels on the high seas for deserters and other persons liable to military and naval service.
The difference upon this point was one of the chief causes of the war of 1812, and the matter has never yet been specifically settled, but it cannot be supposed that the British claim will ever be reasserted. Recent modifications of belligerent rights have not materially limited or affected the right.