Why did the United States bomb Hiroshima and Nagasaki?

The United States dropped atomic bombs on the Japanese cities of Hiroshima on August 6, 1945, and Nagasaki on August 9, 1945, during the final stages of World War II. The primary reasons for the bombings were to bring about a swift end to the war and to avoid a costly and potentially devastating invasion of mainland Japan. Key factors that contributed to the decision include:

• Ending the war quickly: By 1945, the war had already caused immense loss of life and suffering on all sides. The United States and its allies sought to end the conflict as quickly as possible, and the use of atomic bombs was seen as a means to force Japan's surrender without further protracted fighting.
• Avoiding an invasion of Japan: Plans for a conventional invasion of Japan, codenamed Operation Downfall, were being developed, but it was estimated that such an invasion could result in a high number of casualties for both the invading forces and the Japanese civilian population. The atomic bombs were seen as a way to avoid this costly and bloody scenario.
• Demonstrating power: The use of atomic bombs also served to demonstrate the United States' technological and military prowess. This show of force not only aimed to intimidate Japan into surrendering but also to establish the United States' position as a dominant global power in the post-war world, particularly in relation to the Soviet Union.
• Investment in the Manhattan Project: The United States had invested significant resources into the development of the atomic bomb through the top-secret Manhattan Project. Using the bombs on Hiroshima and Nagasaki partly justified the enormous expenditure and effort put into creating these new weapons.

The bombings of Hiroshima and Nagasaki resulted in the deaths of over 100,000 people, most of them civilians, and left a lasting legacy of suffering and devastation. Japan announced its surrender on August 15, 1945, effectively bringing an end to World War II.