I would say Europe has had it easy with the USA subsidizing the defense of those nations with American military power

If it was not for the USA those countries would not have built national welfare systems

The USA gets a lot of political and geopolitical advantages from the arrangement but it's the USA that keeps the peace for over 80 years

From 476 AD to 1945 AD Europe was a battlefield to see who will emerge as the master of that continent

A strong comparison could be made with China's warring States period