Why did the U.S. drop the atomic bomb on Japan?

Answer 1

There were persons opposed to the decision made by President Truman. The reasons go from the weapon killed thousandths of civilians, the living with burn scars all over their bodies and the radiation contamination that killed hundreds of people after the bombing and keep bringing the symptoms to date.

President Truman behold his decision for reasons that go from millions of soldiers would die fighting the Japanese in the mother land because all civilians and the military was trained to fight them to the end and these weapons will bring en end to the war. Also British leaders agreed to use the bomb against Japan and supported Truman. Also, United States was considering the following ways of bringing the long war to an end: invade the Japanese mainland in November 1945, ask the Soviet Union to join the war against Japan, or use the atomic bomb.

Some captured u boats contained nuclear material aboard in the route to Germany and that made the decision to use the bomb harder.

Answer:

In addition to reasons related to the Japanese the Americans also wanted to demonstrate to the Russians (as the Russians were shaping up to be the next major problem to the US) that the US had the capacity to build and deliver atomic weapons. The actual dropping showed the US was willing to cause massive civilian deaths in pursuit of their goals. The use of two bombs demonstrated that the weapon was not a one shot wonder and that the US had "many more" such weapons in reserve.