Let our enemies destroy each other
The Sunnis want to rid the earth of Shiites and vice versa.
It will never end until one side has killed off he other side, which probably means it will never end. So why should one more American life be sacrificed? It is a religious civil war.
We not only should not get involved, but because factions on both sides would like to rid the earth of us (Christians and Jews), let's let our enemies destroy each other. The more we get involved, the more we are hated. Enough already.