the system's borders are rigid, the probability of hegemony is high. The argument of universal reproduction of anarchy can be correct in the European context, "whereas a systematic survey of world history reveals that multipolarity has frequently given way to unipolarity or hegemony." Henry Kissinger, Historian by profession, noted that "theories of the balance of power often leave the impression that it is the natural form of international relations. In fact, balance-of-power systems have existed only rarely in history." Yet based on these rare occurrences, many realists "elevate a fact of life … into a guiding principle of world order." Earlier, political scientist Martin Wight had drawn a conclusion with unambiguous implication for the modern world: Still earlier, Quincy Wright, concluded on the balance of power in world history: Evoking examples of the ancient Chinese and Roman civilizations, Quincy Wright added: The post-Cold War period represents an anomaly to the balance of power theory too. Rousseau defined the theoretical limit how far balance of power can be altered: "Will it be supposed that two or three potentates might enter into an agreement to subdue the rest? Be it so. These three potentates, whoever they may be, will not possess half the power of all Europe." "Within two-and-a-half centuries, only one potentate possessed half the power of all the world, including Europe. In 2008, US military expenditures, including supplemental spending, exceeded those of the rest of the world combined."Stephen Walt, "Imbalance of Power," Foreign Policy, 193: (12 May 2012): p 1, https://foreignpolicy.com/2009/05/12/imbalance-of-power/ Since 2000, the founder of Neorealism, Kenneth Waltz, confessed that "the present condition of international politics is unnatural." "Clearly something has changed." Wohlforth, Little and Kaufman undertook the above-mentioned historical study after they had coped with what they called the "puzzle" of the unipolar stability. Elsewhere, Richard Little wrote: Events since the end of the Cold War "create a potential anomaly" for the theory because the outcome has "left the United States as the sole superpower in a unipolar world ... A major puzzle for realists ... is the fact that unipolarity has not provoked a global alarm to restore a balance of power." The same anomaly stressed seventeen other experts on alliances, Stephen Walt, Randall Schweller, Xiaoyu Pu, John Ikenberry, Robert Pape, T. V. Paul, Jack S. Levy, William R. Thompson, John Lewis Gaddis, David A. Lake, Campbell Craig, Fareed Zakaria, John M., Owen, Michael Mastanduno, Thomas S.