I don't think either one of those was true after after WW1. Russia, though large, was not regarded as a serious military threat to Europe. When attacked by Rus

I don't think either one of those was true after after WW1. Russia, though large, was not regarded as a serious military threat to Europe. When attacked by Russia, Poland (!) beat Russia in the 1920's and gained half of the Ukraine and half of Belarus in the subsequent peace treaty. An although a European nation was no longer the world largest economy, they were still regarded as the powers that mattered. The Washington Naval Treaty on arms control between the wars even gave the US a ship allocation on par with a European nation. The world at the time still revolved around Europe and the actions of European powers. To be premininet in Europe was to lead the world.