When one country or region of the world is facing political upheaval, genocide, or war, what role should the international community play? Should powerful countries such as the United States "police the world," ensuring widespread peace by intervening in such conflicts? Should each nation be responsible for managing its own conflicts? This book delves into the history of armed intervention to explore arguments both for and against military intervention, and to assess when and where it is necessary, if it is ever necessary at all. Full-color photographs, a glossary, and sidebars aid young-adult readers as they explore all sides of this debate.