The USA use of Nuclear Weapons in WWII
The president, Harry Truman, was fully aware of the impact that the atomic bomb and its potential of mass killing and destruction. He knew that if he gave the orders to drop the bomb then it would kill 10,000's of Japanese people. However he also believed that the Japanese would not surrender at any cost. The choice as Truman saw it was either to drop the bomb and kill 10,000's or begin a lengthy ground invasion which would potentially see 100,000's die if not millions on both sides.
The bomb was dropped and 100,000 people are believed to have been killed but the number is not exact. On the 14th of August, Japan surrendered.
Truman's decision was made on utilitarian grounds, by dropping the bomb he hoped to minimise the loss of life and hence end the war with the minimum amount of pain. This reasoning could only be employed by a consequentialist and many people condemned his decision to be mass murder. For the catholic philosopher G E M Anscombe it represents the ends not justifying the means