We defend our trade interests, and lose more than those interests are worth. Let's be honest: Putin could take Paris, but we'd be the only major market to sell to.
We should, in my opinion, withdraw from NATO, and from almost every other treaty. Let China, Russia, and etc., try their hand at empire. It's worth less than the cost of maintaining it. And those countries have crippled their population growth by one-child policies and social nihilism, not to mention by authoritarian regimes that are very unpleasant to live under. Let them try for regional domination, and let them die in the attempt, while we, the United States, continue to grow by immigration and assimilation. Do that, and India and the U.S. will inherit the earth.