Hindsight is very convenient.

My grandfather was an isolationist in the 1930s. My father wasn't. I wasn't born until the 1950s. After I was born, I worshipped my grandfather. What would I have advocated? Who knows?

What makes your question about current politics more relevant than my observation about the fundamental principle of all the great religions? Is that only relevant on Sunday, or when we're talking about people like us? Do not the publicans do the same?

What makes your observation about the Rhineland more relevant than mine about Versailles? The treaty was the foundation of Hitler's power, because it undermined German democracy in the cause of bitter vengeance. For want of a nail, the shoe was lost; for want of a shoe, the horse was lost; for want of a horse, the rider was lost; for want of a rider, the battle was lost; for want of a battle, the kingdom was lost; and all for the want of a horseshoe nail. If one wants to learn from history, one has to learn from all of it.