The War Department ordered 750,000 Purple Heart medals for the invasion of Japan, to be awarded to servicemen killed or wounded. Because of the atomic bomb, they weren't needed, and were stored.(The number actually awarded in WWII was about 965,000.)
Some of them, were awarded during the Korean War, the Vietnam War, and other conflicts. They are still being issued in Iraq and Afghanistan today.
All the combat seen by American forces since WWII still have not equaled the first installment of what was expected in Japan.
In my opinion, the invasion of Japan would not have taken place even without use of the atomic bomb. The US would simply have continued the submarine campaign against Japanese shipping, and the air campaign against Japan itself, and starved and bombed Japan to death. This would have minimized Allied losses, while killing many times more Japanese, and destroying Japan as a nation, a culture, and a people.
One thing people don't grasp is that US war production was still ramping up when it ended. The US Navy canceled more aircraft carriers scheduled to be launched in 1946, than the Japanese Navy had built in its entire history. Henry Ford's production line for B-24 bombers had just gone into operation in Michigan. It took in aluminum stock at one end and launched a bomber every 60 minutes at the other. All that firepower, and nowhere to use it but Japan.
Most of those Purple Hearts would have gone into storage anyway, The people who call the use of the atomic bomb a war crime, would be calling the failure to use it a war crime, with considerably more justification. It's very unlikely that I would be blogging about it, in either case, since my mother was working in a clerical position for Japanese Army Intelligence in Nagoya.