全球智库信息集成服务系统

Today, the United States faces no existential threat; rather, it confronts an unusually wide and diverse array of challenges.

• Russia has reemerged as an aggressor state. China has become more repressive at home and more assertive abroad. Al Qaeda has spawned offshoots and imitators more powerful and more radical than itself. Climate change has advanced, and predictions of climate-related disasters have become more ominous, more imminent, and more credible. Cyberspace has emerged as a new battleground between the forces of order and disorder. Expansion of international travel makes the emergence of new communicable diseases like Ebola more dangerous. The past few years have been a reminder that stability is not the natural state of the international environment, that peace is not self-perpetuating, and that whole regions can descend suddenly into anarchy.