The Sussex agreement.
"The German submarine forces have had in fact, orders to conduct submarine warfare in accordance with the general principles of visit and search and destruction of merchant vessels as recognized by international law, the sole exception being the conduct of warfare against the enemy trade carried on enemy freight ships that are encountered in the war zone surrounding Great Britain. * * *
Merchant ships not to be sunk without warning.
"The German Government, guided by this idea, notifies the Government of the United States that the German naval forces have received the following orders: In accordance with the general principles of visit and search and destruction of merchant vessels recognized by international law, such vessels, both within and without the area declared as naval war zone, shall not be sunk without warning and without saving human lives, unless these ships attempt to escape or offer resistance. See Official Communication by German Foreign Office to Ambassador Gerard, May 4, 1916. (White Book No. 3 of Department of State, pp. 302, 305.)"
Right to make a prize.
There is, of course, no doubt as to the right to make prize of an enemy ship on the high seas, and, under certain conditions, to destroy her, and equally no doubt of the obligation to safeguard the lives of all persons aboard, whether passengers or crew.
Two quotations from a long list of authorities may be given for convenience, one stating the rule and the other the attitude which obtains among civilized Governments. Oppenheim sets forth as among violations of the rules of war:
"(12) Attack on enemy merchantmen without previous request to submit to visit."
The observation in Vattel's "Law of Nations" is peculiarly applicable to the case of the Lusitania:
"Let us never forget that our enemies are men. Though reduced to the disagreeable necessity of prosecuting our right by force of arms, let us not divest ourselves of that charity which connects us with all mankind. Thus shall we courageously defend our country's rights without violating those of human nature. Let our valor preserve itself from every stain of cruelty and the lustre of victory will not be tarnished by inhuman and brutal actions."