People backed up against the wall in a very bloody conflict.
Remember, the US was willing to nuke Japan flat at the end of WW2 because they saw how bloody invading the country could be, thanks to Okinawa. The total projected casualties of nuking Japan (which were made without understanding the effects of fallout, etc...) were massively less than the projected casualties for the invasion.
Remember, the US made so many damn Purple Hearts for that invasion that they were handing them out decades later.