I agree with so many of the points raised in this thread. America was truly burned by WWI, being lied to by President Wilson about our involvement, and then the brutal Spanish Flu epidemic wiping out millions of people toward the end of that conflict. America has always been strongly isolationist, but only since WWII have we had to stride to the front of the world and act as a selective protector of democracy worldwide. I say selectively, because we pick and choose who we want to defend (usually based on a subject political calculus).
To answer the question about how aware today's Americans are of the rise of fascism abroad re: Russia's invasion of Ukraine, I say: very little. And it is because our society is in the last phases of a general cultural decline that cares little for the values that originally created and then sustained it. Read about the Roman Empire. Americans today (generally speaking, of course) are more concerned about their sports teams, happy hour, and posting selfies. I'm jaded, what can I say. We are too busy contemplating our own navels to grasp that democracy and freedom is not a state of nature occurring organically; it must be striven for and defended at every turn. Ask a Ukrainian how quickly their freedom and rights can disappear. America needs to wake up. Today, Ukraine. Tomorrow...who else?