Robert. A. Heinlein
“Anyone who clings to the historically untrue -- and -- thoroughly immoral doctrine that violence never solves anything I would advise to conjure up the ghosts of Napoleon Bonaparte and the Duke of Wellington and let them debate it. The ghost of Hitler would referee. Violence, naked force, has settled more issues in history than has any other factor; and the contrary opinion is wishful thinking at its worst. Breeds that forget this basic truth have always paid for it with their lives and their freedoms.”
There are multiple reasons why a majority of Americans today would just look at you and go "Huh?" when you mention the anniversary of the attack in Beirut. The collective symptoms of those reasons are manifest in the blithering Marxist jack-ass currently infecting the Oval Office.
We've lost the lessons of the past, and now we're going to relearn them in painful ways that could have been avoided.