The twenty-first century has brought challenges to all nations that are strikingly different from those of the twentieth century. Pandemic illness is the most urgent and climate change in the longer-run is the most dangerous. But a more traditional kind of challenge is also reemerging, a world of great power rivalry. Added to this threat will be the continuing spread of dangerous technologies as modernizing nations narrow the technical gap separating them from more advanced nations, and as some of these technologies come within reach of private groups.
Medical challenges that affect all countries may be easiest to meet, although the pandemic may change how normal life functions as a result. Owing to a late start, it will take much longer now to bring stability to the world's climate. In the meantime, the world will have to adapt to more severe environmental conditions.
Great power rivalry, and smaller countries and private groups with grievances against the world order, may be less tractable. This danger will place America in a particularly difficult position. Americans are accustomed to seeing the outside world in terms of two extremes, the short-term and the indefinite long-term. This way of looking at the world is rooted not just in presidential elections that limit policies to intervals of four to eight years but also in American assumptions about the world formed in the twentieth century.
During the Cold War (1947-1989), Americans thought of their security in terms of commitments that had to be sustained over an indefinite period of time. America continued to think this way after the events of 2001. As a result, there was no sense that goals needed to be achieved in a finite amount of time (or needed to be defined from the start with time limits in mind). The rise of China and the recovery of Russia as rival powers tend also to be seen in Washington as open-ended challenges.
It will be a departure for Americans to define longer-term goals in international relations that are not open-ended. Unless public opinion begins to think about time in a new way, though, we will stumble into a dangerous future that might have been prevented with greater foresight.