For Mearsheimer, great powers maximize their relative power; There is an unlimited power struggle, but it is not an appetite for power that pushes, it is a security problem enforced by the anarchic structure of the international system. When all states are capable of harming each other, each one wants to have as much power as possible to be as safe as possible against the attack. This assumption of security motivation and structural causality, of course, brings Mearsheimer closer to Waltz.
What Mearsheimer thinks differently from Waltz is the assertion that his quest for power and security is grasping, but Waltz says it has its limits. So with Waltz, he doesn’t agree on how much power a state wants. Mearsheimer explains the point briefly: For the defensive realists, the international structure gives little encouragement to the states to look for additional power increases; instead, they force them to maintain the current balance of power. The main purpose of states is to protect power rather than to increase power.
On the other hand, offensive realists believe that the status quo forces are rarely found in world politics, because the international system creates strong incentives for states to seek opportunities to gain power at the expense of their competitors, and they want to take advantage of these situations if the debts outweigh the costs. The ultimate goal of a state is to become a hegemon in the system. Mearsheimer’s offensive realism seems to predict far more conflict and war than Waltz’s defensive realism. States are never satisfied; They continue to reach more power, and this power impulse seems compelled to collide. Waltz might claim that power and security accumulation at a very short point from hegemony has resulted in a diminishing marginal return as the costs begin to decrease, and the security purchases do not result in anything. Mearsheimer denied that security increases decreased in value of the margin; In fact, it claims the opposite: a state that has a significant power advantage over its competitors will be more aggressive than confronting a strong opponent, because it has the ability to do so. Mearsheimer thinks that the great powers will fear each other and will explore this power to maximize their share of world power and to continually seek to alleviate this fear: even if the ultimate motive is simply to survive, the states tend to think aggressively against other states. In short, great powers have aggressive intentions. However, aggression does not come from the obvious assumptions of Mearsheimer. This comes indirectly from an unexplained assumption. These great powers have a much higher level of security than the actors of Waltz. While Waltz imagines a satisfying world, we can say that Mearsheimer sees only the maximizers. It seems ironic that these two structural realities differ fundamentally to a unit-level factor: how much security does states want? The security dilemma emphasizes how power and security competition can happen between states that do not want anything other than maintaining the status quo. While no one is actually offensive, the uncertainty about the intentions of others forces each to take protective measures that appear threatening to others. But Mearsheimer has no status quo in his world. All great powers are revisionist and prepare themselves to be offensive. In addition, the security movements included in the offensive realistic scenario are territorial expansion movements, which include taking something from others, rather than simply preparing, as in the purchase of weapons or in the formation of alliances. Thus, although the ultimate goal of the expanding state is security, its de facto behaviour towards achieving this goal can be virtually indistinguishable without raising its reputation. In this world, security needs must be incompatible; not everyone can increase world powers at the same time. There is more security competition, but less security dilemma. From his analysis, Mearsheimer reveals that the best way for a state to survive in anarchy is to take advantage of other states and take power at its own expense. According to him, the best defence is the good offense. As a rule, conquest brings success and profit.The reason why the security dilemma does not properly conform to Mearsheimer’s theory is to relate security and survival behaviour, which is naturally a defensive goal, to offensive behaviour. All states, or at least all great powers try to maximize power, because every power increase increases the chances of survival in an anarchic system. For this reason, there is almost no status quo authority. Mearsheimer tests and demonstrates the empirical validity of his theory by examining six major cases of power behaviour: from 1868 to 1945 Japan; from 1862 to 1945 Germany; from 1917 to 1991 the Soviet Union; from 1861 to 1943 Italy; from 1792 to 1945 Great Britain; and from 1800 to 1990 the United States. He seeks to show that the history of powerful ruling policies primarily involves the conflict of revisionist states and that the only status quo in the story is the regional hegemons. The evidence also shows that when the great powers have a place in which they can change the balance in their favour, they do not hesitate to do this, and the appetite for power does not diminish. The offensive realist states are not always offensive. They sometimes have to deter and involve competitors who want to gain power at the expense. In this defensive role, there is a choice between the balancing and the buck-passing. Balancing means acting to maintain an existing power distribution. Buck-passing is to be cautious and to take no action to shift the changing resistance load to an ally or other states. Mearsheimer argues that the structure of the system and geography will be decisive for the choice. Bipolar, balanced multipolar and unbalanced multi-polar are possible system structures. Buck-passing is more applicable in the system of balanced multipolar. Mearsheimer provides little empirical support or theoretical value for bandwagoning, preferring to be an ally, rather than against a powerful state. Some theorists think “bandwagoning” is the opposite of balancing. At this point, we figure out the difference between Mearsheimer’s and Waltz’s neorealism understanding; power maximizing versus power balancing. Mearsheimer also uses three structural models to assess the causes of the war. The bipolarity is peaceful and open to war. The most peaceful one is unbalanced multi-polarity, and somewhere between them there is a balanced multi-polarity. Focusing on offensive realism tools in Europe and Northeast Asia, Mearsheimer predicts greater instability, perhaps war in these regions over the next 20 years. The forecast is based on two central variables, depending on whether US troops will be deployed in these regions and whether there are possible changes in regional power structures. Mearsheimer expresses his greatest fears for Northeast Asia and China. He presents two scenarios: one where China’s economic growth slows down, Japan is the richest state in Asia, and China continues to grow rapidly and surpass Japan. Mearsheimer ends several open policy recommendations for the United States: Engage China and surround it. Do what you have to do to slow China’s growth.