I have seen this happen twice. I was just a child at the end of the Vietnam War. People had cruelty brought home to them and they reconsidered being fuckers to other countries of people who are different from them.
But that didn't last too long. Cruelty became a viable measure by the time I was an adult. Murdering people in the Middle East for oil was a good thing in the 90s. We continued in the next decade after people from the same part of the world punched us back hard.