Vulnerable Sovereignty

According to recent reports, the U.S. government is putting pressure on several of its allies to end the use of child soldiers. The countries in question are Chad, the Democratic Republic of Congo, South Sudan, and Yemen. According to the reports, the international community is expecting the U.S. to take steps to end the practice of these much smaller countries. Given our recent discussions of vulnerability and community I have begun to wonder what it is that makes us responsible for policing the actions of these countries. While I am aware of the reputation that the U.S. has given itself as an international policeman, I wonder if the expectations placed upon the U.S. by the international community are not more complicated than simply the fact that the U.S. has given itself a certain reputation. Could it be that the reason that we are expected the reform these smaller countries is that they are viewed as much more vulnerable than we are as Butler may point out? In other words, I wonder if the nation that is considered the least vulnerable suddenly becomes responsible for all of the those more vulnerable countries with whom it associates. Assuming that vulnerability is the difference that makes us responsible for the actions of these nations that we have allied ourselves with, what would the consequences be if we were seen as equally as vulnerable as these countries that we are expected to police? If our responsibility is based upon vulnerability, would that responsibility dissapear entirely as result of equality or would the responsibility fall upon someone that is outside of the group who has less vulnerability? Of course, underlying all of these questions is whether the recognition of vulnerability gives us more or less right to act upon the sovereignty of another country. In the current situation, I am curious both what the current system would say and what Butler system would propose for this problem of policing.