No transatlantic passenger liner, and certainly none carrying American citizens, had been torpedoed up to that time. The submarines, therefore, could lay their plans with facility to destroy the vessel somewhere on the way from Fastnet to Liverpool, knowing full well the easy prey which would be afforded by an unarmed, unconvoyed, well-known merchantman, which from every standpoint of international law had the right to expect a warning before its peaceful passengers were sent to their death. That the attack was deliberate and long contemplated and intended ruthlessly to destroy human life, as well as property, can no longer be open to doubt. And when a foe employs such tactics it is idle and purely speculative to say that the action of the Captain of a merchant ship, in doing or not doing something or in taking one course and not another, was a contributing cause of disaster or that had the Captain not done what he did or had he done something else, then that the ship and her passengers would have evaded their assassins. [Sidenote: The Captain and company not negligent.] I find, therefore, as a fact, that the Captain and, hence, the Cunard Company were not negligent. The importance of the cause, however, justifies the statement of another ground which effectually disposes of any question of liability. It is an elementary principle of law that even if a person is negligent recovery cannot be had unless the negligence is the proximate cause of the loss or damage. There is another rule, settled by ample authority, viz.: that, even if negligence is shown, it cannot be the proximate cause of the loss or damage if an independent illegal act or a third party intervenes to cause the loss. The question, then, is whether the act of the German submarine commander was an illegal act. [Sidenote: International law.] The United States courts recognize the binding force of international law. At least since as early as June 5, 1793, in the letter of Mr. Jefferson, Secretary of State, to the French Minister, our Government has recognized the law of nations as an "integral part" of the laws of the land. To ascertain international law, "resort must be had to the customs and usages of civilized nations; and, as evidence of these, to the works of commentators and jurists. * * * Such works are resorted to by judicial tribunals * * * for trustworthy evidence of what the law really is." Let us first see the position of our Government, and then ascertain whether that position has authoritative support. Mr. Lansing, in his official communication to the German Government dated June 9, 1915, stated: [Sidenote: Mr. Lansing's communication.] [Sidenote: Responsibility of the German Government.] [Sidenote: A principle of humanity.]