Peacekeeping is a worthwhile international endeavor. Often times, peacekeepers can go into countries and try to broker deals with current political regimes much easier than any other military intervention. Peacekeepers can also help with humanitarian aid and to bring help to the region if necessary. They are not the only endeavor, but they are an important one.
Yes, and international endeavor is needed for peace. War has been witnessed since man's realization of self. It has seen many injustices and vindications. There will be nations at war, but it's worth every ones effort to keep peace amongst men. Societies have a way of being "selfish". Life isn't just about what is in your domain. Compassion is needed to better understand others position. Help spread peace and ultimately life, by sharing ones viewpoint. We will not last without these efforts.