The Thucydides Trap refers to the historical pattern where a rising power threatens to displace an established power, often leading to war. The term comes from Thucydides, the ancient Greek historian who described the Peloponnesian War between rising Athens and dominant Sparta. In modern times, the concept is often applied to the rivalry between the U.S. and China, where many analysts believe that China’s rise could lead to conflict with the U.S., just as previous shifts in global power have led to war. The theory suggests that such power transitions are inherently dangerous and require careful management to avoid escalation.