Aaron L. Friedberg in The National Interest:
Throughout history, relations between dominant and rising states have been uneasy—and often violent. Established powers tend to regard themselves as the defenders of an international order that they helped to create and from which they continue to benefit; rising powers feel constrained, even cheated, by the status quo and struggle against it to take what they think is rightfully theirs. Indeed, this story line, with its Shakespearean overtones of youth and age, vigor and decline, is among the oldest in recorded history. As far back as the fifth century BC the great Greek historian Thucydides began his study of the Peloponnesian War with the deceptively simple observation that the war’s deepest, truest cause was “the growth of Athenian power and the fear which this caused in Sparta.”
The fact that the U.S.-China relationship is competitive, then, is simply no surprise. But these countries are not just any two great powers: Since the end of the Cold War the United States has been the richest and most powerful nation in the world; China is, by contrast, the state whose capabilities have been growing most rapidly. America is still “number one,” but China is fast gaining ground. The stakes are about as high as they can get, and the potential for conflict particularly fraught.