In today's interdependent world, United States confronts extraordinary international political, security and humanitarian challenges, from climate change to nuclear proliferation to poverty and instability in regions confronting poverty and state failure. To exercise effective leadership and make progress on these issues, the United States must advance a vision for responsible U.S. global engagement that emphasizes international cooperation, affirms the strong connections between today's most pressing global issues, and recognizes that progress on compelling global problems will require the active support of friends, allies and other major stakeholders in the international community. The United States will only gain such cooperation and support if it exercises power and influence in a manner that is widely perceived as legitimate, and that clearly demonstrates foresight and responsibility to future generations. This approach embodies principles that have marked U.S. foreign policy at its most effective.