Editorial: 80 yrs since Potsdam, Japan must defend rule of law against great power politics

The Mainichi

26-07-2025

July 26 marks 80 years since the 1945 Potsdam Declaration, in which the United States, Britain and China called on Japan to surrender in the final stages of World War II.
The declaration was a final ultimatum, announced during the Potsdam Conference where the leaders of the U.S., Britain and the Soviet Union discussed the postwar governance of Germany and Japan following Germany's defeat.
Japan ignored the ultimatum, and the United States used this as justification to drop atomic bombs on Hiroshima and Nagasaki. The Soviet Union also broke its neutrality pact with Tokyo, joined the declaration, and invaded Japanese-controlled territory.
Then Prime Minister Kantaro Suzuki's Cabinet ultimately decided to surrender, but was unable to persuade the hardline military leadership to do so. It was only through the "sacred decision" of Emperor Hirohito (posthumously Emperor Showa) that Japan accepted the declaration, bringing the war to an end.
Until that moment, Japan pinned its hopes on Soviet mediation for peace. A key factor behind this miscalculation was Japan's failure to grasp the existence of the Yalta Agreement, signed five months earlier by the U.S., British and Soviet leaders.
In that secret deal, Washington, eager to end the war quickly, asked Moscow to enter the war against Japan, and in return agreed to Soviet demands for the cession of southern Sakhalin and the Kuril Islands.
Then U.S. President Franklin D. Roosevelt, in doing so, set aside the "no territorial expansion" principle he had championed in the Atlantic Charter, and pandered to Soviet Premier Joseph Stalin.
Roosevelt knowingly accepted not only the Soviet claim to southern Sakhalin, lost by Russia to Japan in the Russo-Japanese War, but also the Kuril Islands, which had belonged to Japan even before that -- a move that was clearly excessive.
While such wartime diplomacy may have been realist, the U.S.-Soviet deal left a lasting scar. The Northern Territories issue, with Russia's illegal occupation of a clutch of islands off Hokkaido, remains unresolved to this day.
The calculations of great powers also led to a divided world. The postwar partition of Germany by the U.S., Britain, France and Soviet Union, and the U.S. military occupation of Japan, triggered the start of the Cold War. The struggle for spheres of influence sparked a fierce arms race, pushing the world to the brink of nuclear war. We must reflect once more on the harsh history of the 20th century.
Today, there is growing concern over great power politics surrounding the war in Ukraine. Russia has not hesitated to threaten to resort to nuclear arms, and Washington has even indicated a willingness to accept the partial cession of Russian-occupied Ukrainian territory to Moscow.
If the self-serving logic of major powers is allowed to prevail, it risks a return to the age of imperialism. We must not turn back the clock.
The Potsdam Declaration, which called for respect for fundamental human rights, became the foundation for postwar Japan's democracy and its path as a peaceful nation. Rejecting the arbitrary actions of great powers that shake international order and defending the rule of law is the role Japan must play now.