U.S. keeps Soviet Union out after successful atomic bomb test

 While Japan became increasingly resigned to repeated U.S. bombardments on the mainland, the Allied Powers were drawing up demands. On July 26, 1945, they announced the Potsdam Declaration, defining the terms for Japan’s surrender.

 The 13 clauses of the declaration included:

 Regarding the Emperor system, Clause 12 only stated, “The occupying forces of the Allies shall be withdrawn from Japan as soon as these objectives have been accomplished and there has been established in accordance with the freely expressed will of the Japanese people a peacefully inclined and responsible government,” while Clause 5 stated: “The ­following are our terms. We will not deviate from them. There are no alternatives. We shall brook no delay.”

 U.S. President Truman, British Prime Minister Winston Churchill and General Secretary of the Communist Party of the Soviet Union Josef Stalin met in the suburbs of Berlin for the Potsdam Conference from July 17, 1945. The declaration which had been drafted by the U.S. government was signed by Truman, Churchill and Chiang Kai-shek, President of the Republic of China, who did not attend the conference.

 Why wasn’t Stalin invited to join in signing the declaration?

 U.S. Secretary of State James Byrnes later explained that Truman and Churchill did not want to inconvenience the Soviet Union—which was not at war against Japan—by dragging it into the war.

 On July 16, a day before the conference started, the United States successfully tested an atomic bomb for the first time. Buoyed by this development, Truman felt the Soviet entry into the war was no longer necessary to end the conflict and decided to keep the Soviet Union out of the talks on the Potsdam Declaration.

 For Stalin, signing the Potsdam Declaration with Britain, China and the United States could have meant the Soviet Union could shirk international criticism of declaring war on Japan in violation of the Japanese-Soviet Neutrality Pact. However, things did not pan out as Stalin hoped.

 At 5 p.m. (11 p.m. Japan time) on August 8, two days after an atomic bomb was dropped on Hiroshima, Soviet People’s Commissar for Foreign Affairs (Foreign Minister) Vyacheslav Molotov read out a statement to Ambassador to the Soviet Union Naotake Sato in Moscow. “The Soviet Union will be at war against Japan from tomorrow, August 9,” Molotov said.

 The statement said, “In view of Japan’s refusal to surrender, the Allies asked the Soviet government to join in the war against Japanese invaders. The Soviet government, which is faithful to all obligations of its allies, accepted a proposal of the Allied Powers and participated in the Allied Powers’ declaration [Potsdam Declaration] dated July 26 this year.” Sato told Molotov that he wanted to convey the message of their talks to Japan via telegram because there was still time before midnight when Japan and the Soviet Union would technically be at war. Molotov accepted the request. However, Sato’s telegram did not reach Japan, for reasons that remain unclear.

 The Soviet Union planned to make a surprise attack, entering the war against Japan in Manchuria at midnight on August 8. Sato received the statement at 5 p.m. on August 8 in Moscow, which was 11 p.m. in Manchuria. Only one hour remained before the Soviet Union joined in the war. Just before noon on August 10, Foreign Minister Shigenori Togo in Tokyo officially received the statement on the declaration of war from Soviet Ambassador to Japan Jacov Malik. By then, the Red Army had already moved deep into Manchuria. Four months earlier on April 5, the Soviet government notified Japan it would not renew the Japanese-Soviet Neutrality Pact. However, the pact was binding until April 1946. The Soviet entry into the war was an obvious violation of the pact.

 What lay behind the Soviet decision to join the war? In December 1941, right after Japan’s attack on Pearl Harbor, Stalin told British Foreign Secretary Anthony Eden, who was visiting Moscow for talks on forming an alliance, that the Soviet Union probably would enter the war against Japan in the future. In the meantime, Soviet diplomatic authorities had already begun discussions on measures to secure “an exit to the Pacific Ocean.”

 In July 1944, Malik submitted to Stalin a report titled “Issues concerning Soviet-Japanese relations.” The report stated demands to substantially expand the Soviet territories, including not only Southern Sakhalin, which Japan had acquired at the Russo-Japanese negotiations at Portsmouth in 1905, but also the Kuril Islands and neutralizing Tsushima or making it a Soviet naval base; internationalizing the straits of Tsugaru, Kanmon and Bungo; and making several Japanese ports into free ports.

 However, according to Keio University Professor of Modern Russian History Shinji Yokote, Soviet diplomatic authorities believed the war between Japan and the United States would enable the Soviet Union “to reap what others have sown.” The authorities considered that the Soviet Union could or should get Sakhalin and the Kuril Islands without firing a shot, Yokote said. It was Stalin who decided to enter the war: He judged that it would be impossible for the Soviet Union to expand its influence in the Far East without making some military contribution.