Intervention between Countries in problem

I believe that if a country is having problems, such as problems with Genocide, a higher power should come to the help. The United States should be able to intervene because someone has to stop the fighting. The US has one of the largest and strongest Army/ Forces, and they would be able to stop the situations. With the Unites States aid, countries should be able to solve problems, while saving thousands, if not, millions of civilian lives.