Gian Gentile is a retired U.S. Army colonel and former director of the military history program at the U.S. Military Academy at West Point. There is a popular view in America, within the military and among civilians, that when it comes to war, U.S. service members fight and die for each other, for their buddies on their right and left.

That is one reason many people were appalled last month when President Donald Trump said of four soldiers who died in the Middle East amid the conflict with Iran, “They said, and all of them said very strongly, ‘We can’t let, we cannot let Iran have a nuclear weapon’” — in effect, they agreed with his war aims.