The UN is flawed and needs to get rid of the security council and only allow liberal democracies to vote, they already have the standards for this. It was a deal with the Devil, Stalin, at its birth and its powerlessness resulted from the paranoia and lack of good will of a psychopath who's only real goal was to expand or restore the Russian empire, he was a communist imperialist and Mao followed suit, same personality type as was the asshole in North Korea. After the war America had the lion's share of the world economy, but today make up about 25% of the global economy and they live more or less by the rule of international law. However future military adventures without international sanction will result in the same treatment the Russians are getting, ditto for China. The world is too interdependent today and no country can go it alone and prosper, most would starve, even modern US arms are made by allies or vital components for them are. Yes, America had a lot of economic power, a financial empire that shadowed the later British empire after the second world war, but it was only an economic empire that supported strongmen in some places because of the cold war. Now that the cold war is over America's foreign policy echoes that of other liberal democracies which is the promotion of liberal democracy globally, it is our only chance for survival and responsible government IMO.