The Russian invasion of Ukraine has triggered the most dangerous international conflict in decades with ominous implications. It has already resulted in much death, destruction and displacement in Ukraine. A disruption in food supplies may lead to famine in West Asia, Latin America and Africa. And there is a possibility of the war escalating into something unthinkable. Understanding the root causes of the crisis is essential if we are to prevent it from getting worse and to find a way to bring it to a close. What role have the U.S. and NATO played historically and currently in Ukraine? What might a peace settlement look like?