Visit and search is the right of a belligerent warship, under certain conditions, to board a neutral merchant ship in order to verify its true character.
Article 63 of the Declaration states that "Forcible resistance to the legitimate exercise of the right of stoppage, search and capture involves in all cases the condemnation of the vessel.
At the Hague Convention of 1907, the question of the liability to search of mail-ships gave rise to much discussion based on incidents arising out of the Boer and Russo-Japanese Wars.
It was ultimately decided under a separate article of the Hague conference that postal correspondence of neutrals and even of belligerents, and whether official or private, found on board a neutral or even an enemy ship should be "inviolable", and that though the ship should be detained, this correspondence had to be forwarded to its destination by the captor "with the least possible delay".
[3] According to the U.S. Navy, Under the law of armed conflict, belligerent warships or aircraft may visit and search a merchant vessel for the purpose of determining its true character, i.e., enemy or neutral, nature of cargo, manner of employment, and other facts bearing on its relation to the conflict.