Abstract：At the turn of the twentieth century, the old rivals—England and America—gradually became friends, and the former friends—England and
Germany—turned confrontational. Structural factors—geopolitical conflict, economic competition, or regime difference—and individual agency cannot explain
the two reversals. This article uses the concept of“robust actor”to explain the
mutual influence of these states’crisis response and the change of their relationship structure. Specifically, the German emperor Wilhelm II was unable to steer the delicate alliance system left by Bismarck, and Germany’s dominant role in the power network was thus gradually dismantled and even locked in by its rivals and allies. England became the new robust actor among great powers and forged a hedging alliance structure, appeasing America while restraining Germany with ambiguity. Ironically, Germany and England clashed in World War Ⅰ
when their relationship just was repaired, which was beyond their calculation.
The conflict happened because Germany miscalculated England’s strategic ambiguity, and England had to respond to Germany’s military adventurism. This
study also demonstrates that historical change is often not structural factor-driven linear development but comprises reiterated reversals emerging from multiple sequences of events.
