Sacrifice for..?, California

Walking around this immense war-cemetery and reading the headstones makes me wonder about American people. Each and every one of these crosses represents a American man or woman that has died as a soldier. But not defending his home country, not even close to it. They died fighting over a piece of dirt on the other side of the world, against an enemy that was no threat to home. Bruce, 19 years old, died in Vietnam. Kevin, 18 years old, died in Korea. Mike, 19 years old, died in Cambodia. John, 17 years old, died in Iraq. Philip, 20 years old, died in Lebanon. For what was this sacrifice? There are many of these cemeteries across the USA. I wonder if anyone knows how many have died.
