The use of atomic weaponry against Japan in World War II was unjustified.

Rebuttals to opponents contentions1. Common defenseMy opponent's case shows a false dilemma, that only a land invasion or atom bomb would force the Empire of Japan to surrender. He also uses an unusual justification by using the preamble to the Constitution and by comparing D-Day to the hypothetical operation Olympic. Contrary to that false dilemma the Empire of Japan was already teetering as a result of heavy aerial bombardment and the suffocating blockade that prevented supplies from entering the resource poor nation."The use of [the atomic bombs] at Hiroshima and Nagasaki was of no material assistance in our war against Japan. The Japanese were already defeated and ready to surrender because of the effective sea blockade and the successful bombing with conventional weapons... The lethal possibilities of atomic warfare in the future are frightening. My own feeling was that in being the first to use it, we had adopted an ethical standard common to the barbarians of the Dark Ages. I was not taught to make war in that fashion, and wars cannot be won by destroying women and children." -Fleet Admiral William D. Leahy, Chief of Staff to President Truman. In addition the Soviet offensive, that occurred in August 9th exactly three months after Nazi Germany's defeat, would have rendered the use of the atom bomb unnecessary as the Soviet offensive shattered the Kwantung army, took the 4 northern islands (part of the Kuril island chains) and pushed the IJA from Korea past the 38th parallel.(http://en.wikipedia.org......(1945)) (The Wikipedia reference has most of the sources that I used)2. War is warFirst point Tit-for-tat.My opponent believes that the compensation of numbers for tenacity justifies state terrorism. It is true as my opponent states that, "The Japanese were throwing every available weapon they had at us including the fearful kamikaze pilots. This was a very strong weapon because the emotional toll fighting an enemy that isn't afraid of death is huge." However, this was all to realize the conditional surrender of Japan. The Empire was not naive to think that it would win a prolonged war against the allies. Instead it sought conditional surrender to protect the institution of the Emperor. The defensive operation of the Military Junta in the case of an American invasion, the Ketsugo-Sakusen, was designed to force so many American casualties to force the American people to allow an armistice with which the Empire could avoid humiliation for the military and avoid a Versaille style disarmament. (Racing the Enemy: Stalin, Truman, and the Surrender of Japan. The Belnap Press of Harvard University Press, 2006. ISBN 978-0-674-01693-4) Second point Pearl Harbor, a slight digression.Thank you for stating that Pearl Harbor was deliberate surprise attack and that the only the Imperial Military Junta was to blame when in reality it wasn't. When the Second Sino-Japanese war erupted in 1937 the actions of the Empire turned the West sharply against the Empire of Japan, leading the US to freezing all war time assets of the Empire which were crucial to supplying the Imperial war machine. The Empire tried to negotiate until late November. However by then negotiations were deemed futile by Hideki Tojo, and the 14 part message was sent to the Washington Embassy to deliver a veiled declaration of war. Unfortunately, due to IJA interference or the incompetence of the Embassy staff, the veiled message of war was never transcribed prior to the attack. Which lead to the "surprise attack" on Pearl Harbor. In truth Pearl Harbor was not a true surprise attack but a break down of military intelligence combined with the audacity of Admiral Yamamoto, but I digress.3. The Empire had a choice My opponent states, "The 13th point in the declaration states: "We call upon the government of Japan to proclaim now the unconditional surrender of all Japanese armed forces, and to provide proper and adequate assurances of their good faith in such action. The alternative for Japan is prompt and utter destruction".However, I doubt that my opponent understands what unconditional surrender meant to the Imperial Japanese military. Unconditional Surrender to the Empire of Japan meant that the US could force its brand of Victor's Justice on the Imperial Military (they feared a Treaty of Versaille's style of disarmament), depose the Showa Emperor, and force the Empire of Japan to be exploited by the US. None of which could be accepted by the Imperial Military regime. In addition the wording of the Potsdam declaration was a rehash of the Cairo Declaration, which states the same points stated in the Potsdam declaration and was rejected by the previous regime. Considering how none of the concerns of the Empire of Japan was alleviated in the declaration it is logical that the declaration be rejected by the Junta and that the Empire of Japan plan to implement two policies, 1. the Ketsugo Sakusen to force the allies to make favorable conditions for an armistice, or 2. Try to get the USSR, the only Allied power who was not a signatory of the Potsdam declaration to mediate the war between Japan and the Allies. (Racing the Enemy: Stalin, Truman, and the Surrender of Japan. The Belnap Press of Harvard University Press, 2006. ISBN 978-0-674-01693-4) Before I turn it back to my opponent let me quote Leo Szilard the man who helped start the Manhattan project, "Great power imposes the obligation of exercising restraint, and we did not live up to this obligation. I think this affected many of the scientists in a subtle sense, and it diminished their desire to continue to work on the bomb."