Why should we be concerned about and involved with problems around the globe? The answer is fairly straightforward. We are an empire. Now, it is true that we have used trade agreements and defense alliances to create this empire rather than the traditional use of military force. But, we are an empire nonetheless. Furthermore, our standard of living depends on natural resources, and finished goods that come from all over the world. Accordingly, we have a stake in almost everything that happens around the globe.
This global dependence, combined with our trade agreements and defense alliances, means that we cannot unilaterally dictate terms of our relationships with other countries without seriously disrupting our standard of living. These are issues that all empires have faced, usually without long-term success.