The requirement of a declaration of war prior to the commencement of hostilities was established by the Hague III Convention on the Opening of Hostilities of October 18, 1907. This treaty, which went into force on January 26, 1910, was intended to "ensure the maintenance of pacific relations" and thus asserted "that hostilities should not commence without previous warning." More specifically, Article I holds that "hostilities . . . must not commence without previous and explicit warning, in the form of either a reasoned declaration of war or an ultimatum with conditional declaration of war." In accordance with these treaty obligations, Japan alleged that the attack on Pearl Harbor was not a "sneak" attack upon a nation at peace as the Fourteen-Part Message was in fact a declaration of war. As such, the Japanese attacked only after a lawful declaration of war. There are, however, a number of problems with this argument.
First, this supposed declaration was not delivered by the Japanese embassy in Washington, DC until after 2:00PM, well after the commencement of the Pearl Harbor attack. The Japanese argue that this was not a breach of the prohibition on undeclared attacks as the decision to go to war was not made until immediately prior to the attack on Pearl Harbor. Moreover, the message was expected to be given to Secretary of State Cordell Hull prior to the attack, at the earliest time that warning could reasonably have been provided. The delay was due in part to a belated decision to deliver the message to Washington instead of the U.S. Embassy in Tokyo. And, although the telegram arrived at the embassy in time, problems decoding and translating it into English further added to the delay, ensuring that it would not arrive on time.
While these factors were responsible for the delays on Dec. 7 that caused the warning to be received after the attack, allegations that the decision to go to war was not made until just prior to the attack are not supported by the actions of the Japanese government leading up to the attack. After months of military and diplomatic planning, the decision for war with the United States was formally made on September 6, at a conference managed by the chief advisor to Emperor Hirohito, Marquis Koichi Kido. The rough draft of the plan was submitted on September 13, 1941 and training exercises occurred for the next several months. In fact, the attack was initially set for November 21 (with the 23rd as an alternative) but Admiral Shigeru Funkodona, important in planning the attack, felt that more training was needed. Clearly, the decision to go to war was not a last second one, made when Japan felt they had no choice but to respond to the U.S. economic sanctions with force. This becomes especially clear when one considers the orders given to Vice Admiral Chuichi Nagumo, leader of the attack: If spotted by the United States before December 6, he was to call off the attack and return home, if spotted on December 6, he was to use his own judgement, and if spotted on December 7, he was committed to continue with the attack. Such orders hardly seem those given to the commander of an attack authorized only immediately beforehand.
Second, even if delivered on time, this telegram merely asserted that the Japanese government considered it "impossible to reach an agreement through further negotiations." In his memoirs, Foreign Minister Togo asserted that "Japanís notification was legally valid because it conformed to a precedent, and the head of the U.S. government had no doubt that the notice meant war." Others in the Foreign Ministry clearly disagreed, as evidenced by a protocol written by the Political Affairs Bureau of October 1945 concluding that "the final memorandum submitted in Washington on December 7, 1941 did not mention the commencement of hostilities nor the exercise of freedom of action, and therefore, it could not be legally deemed as qualifying for declaration of war notice." Although the credibility of this statement is suspect given the American domination of the Japanese government after August 1945, its point is quite accurate. The Fourteen-Part Message did not even definitively cease negotiations and the implication that this language in the fourteenth part is somehow a declaration of war is strained at best.
and most strikingly, officials in the Japanese government were aware that
this was not a proper declaration of war. In fact, the Foreign Ministry
did draft a formal declaration
of war which was never sent to the United States and remained buried
in the Foreign Ministryís Historical Archive until unearthed in 1997 by
Professor R.J. Butow at the University of Washington.
This latter document was written by the same man who wrote the Fourteen-Part
Message, Mr. Kase, then Director of American Division I in the Foreign
Ministry; both documents were written at the behest of Foreign Minister
Given the existence of this true declaration of war, the sending of the
Message in its place is a clear sign that the Japanese government knew
that the telegram was not a decisive declaration of war and yet still sent
only this message prior to the attack on Pearl Harbor. The only reasonable
implication from these events is that the Japanese did not want to warn
the Americans, yet felt honor-bound to provide some form of warning. This
explanation is well supported by the events of December 6-7. To ensure
complete surprise, Admiral Isoroku Yamamoto, leader of the attack, wished
the United States to be lulled by continuing negotiations.
Nonetheless, he felt that prior warning was required, a view generally
unsupported by the Japanese Navy which was fearful of a possible leak of
the secret operation. At the Liaison Conference, held after the Imperial
Conference of December 1 wherein the final decision to wage war against
the United states and Great Britain was made, the Chief of the Naval Staff,
Nagano, and his Vice-Chief, Ito, demanded that Togo not cease negotiations
prior to the attack.
However, Yamamotoís view was supported by Foreign Minister Togo who claimed
that a lack of prior notification "did not meet the standards of normal
diplomatic procedures, and would harm Japanís honor and dignity."
While the message eventually sent did not truly provide prior warning,
its transmission does support a belief on the part of the Japanese government
that prior warning was required.