Throughout history, times of internationalism brought about times of prosperity and economic/intellectual expansion. When nations/civilizations turn inward, they fall behind. The end of internationalist Rome brought the Dark Ages. We didn't reawaken until the Crusaders and Marco Polo brought Easter knowledge, tastes, and trade back to Europe. Likewise, the when the Islamic Caliphate was at its greatest, the best minds of Europe and Asia flocked to the universities of Baghdad. When the Mongols destroyed this, Islam fell into a long decline. If Trumpian populism succeeds in the West, we will end up in another Dark Ages. The United States was a second rate power going into World War I. The influx of scholars fleeing Fascism gave us the technical edge we needed to beat the Axis powers to the Atomic Bomb. After WWII, it was von Braun and his team who got us to the moon.