65 years ago, plus one day, the US dropped the only atomic bomb ever used in war (which is kind of ironic, considering how much we rail against countries that have massive bombs).
Dwight D. Eisenhower believed the bomb was unnecessary and we dropped it only to scare the Russians into listening to us after the war.
"In 1945 ... , Secretary of War Stimson visited my headquarters in Germany, [and] informed me that our government was preparing to drop an atomic bomb on Japan. I was one of those who felt that there were a number of cogent reasons to question the wisdom of such an act.... During his recitation of the relevant facts, I had been conscious of a feeling of depression and so I voiced to him my grave misgivings, first on the basis of my belief that Japan was already defeated and that dropping the bomb was completely unnecessary, and second because I thought that our country should avoid shocking world opinion by the use of a weapon whose employment was, I thought, no longer mandatory as a measure to save American lives. It was my belief that Japan was, at that very moment, seeking some way to surrender with a minimum loss of 'face.'
Here's an interesting site that debates the decision.
I also found an interesting question from someone posting a thought. That person asked how we'd feel if Nazi Germany dropped a bomb on New York, killing hundreds of thousands of people. We'd be a tad upset and call them all kinds of terrible things.
Why, why, why would we drop two bombs on cities?
Yes, that was a long time ago. It is easier on an emotional level, to discuss something from the past than the emotionally-charged debates about current military engagement. At the time, anyone who decried the dropping of the bomb would've been mocked, called "un-American" or all kinds of other "shape up or ship out" type of threats/ insults. But decades later, we realize the dropping of the bomb was 1) unnecessary for ending the war and 2) influenced by decisions beyond the war with Japan.
If the US did something that at the time was supported, but later in history revealed to be horrifically evil and completely unnecessary, doesn't that mean there's the possibility that the same type of situation exists now?
Most main-line type of citizens supported the Vietnam war at the time, but very few people would defend it's necessity now.
Can we learn from the lessons of history or do we have to keep repeating the cycle of taking innocent civilian lives in wars that are almost pointless, at best, and completely unjust, at worst.