The Tragedy of Great Power Politics

A state's power in international politics, Mearsheimer argues, derives from the strength of its military for two reasons: because land force is the dominant military power in the modern era, and because large bodies of water limit the power projection capabilities of land armies.

Mearsheimer argues that the presence of oceans in the world prevents any state from reaching world hegemony. He posits that large bodies of water limit the power projection abilities of militaries and thus naturally divide up powers in the globe.

He uses the example of the isolation provided to Britain by the English Channel, which allowed it to act as an offshore balancer on mainland Europe. Britain, he argues, never had ambitions to control or dominate continental Europe. Instead it aimed only to maintain the balance of power and ensure that no state could become so powerful as to achieve regional hegemony on the continent. For much of the 19th century, Britain had an industrial capacity that would have allowed it to easily invade and dominate much of Europe.

However, Britain chose not to attempt domination of the continent, in part because it calculated that its aims of achieving security could be more cheaply achieved if the European powers could be played off against each other. By doing so, the European powers would be occupied on the European continent and unable to challenge Britain across the English Channel or interfere with Britain's economic interests in Asia and Africa.

Therefore, the central aim of American foreign policy is to be the hegemon in the Western Hemisphere only, and to prevent the rise of a similar hegemon in the Eastern Hemisphere. In turn, the proper role for the United States is as an offshore balancer, balancing against the rise of a Eurasian hegemon and going to war only as a last resort to thwart it.

Other scholars have disputed whether the stopping power of water actually makes conquest harder.[4]

In addition to their principal goal, which is survival, great powers seek to achieve three main objectives. Their highest aim is to achieve regional hegemony. Mearsheimer argues although achieving global hegemony would provide maximum security to a state, it is not feasible because the world has too many oceans which inhibit the projection of military power. Thus, the difficulty of projecting military power across large bodies of water makes it impossible for great powers to dominate the world. Regional hegemons try strongly to prevent other states from achieving regional hegemony.

Instead, they try to maintain an even balance among of power in regions and act to ensure the existence of multiple powers so as to keep those multiple powers occupied among themselves rather than being able to challenge the regional hegemon's interests, which they would be free to do if they were not occupied by their neighboring competitors. Mearsheimer uses the example of the United States, which achieved regional hegemony in the late 1800s and then sought to intervene wherever it looked as though another state might achieve hegemony in a region:

• Imperial Germany during World War I
• Nazi Germany during World War II
• Imperial Japan during World War II
• Soviet Union during the Cold War

Great powers seek to maximize their share of the world's wealth because economic strength is the foundation of military strength. Great powers seek to prevent rival powers from dominating wealth-producing regions of the world. The United States, for example, sought to prevent the Soviet Union from dominating Western Europe and the Middle East. Had the Soviets gained control of these areas, the balance of power would have been altered significantly against the United States.

Mearsheimer asserts that great powers seek nuclear superiority over their rivals. Great powers exist in a world of multiple nuclear powers with the assured capacity to destroy their enemies called mutually assured destruction (MAD). Mearsheimer disagrees with the assertions that states are content to live in a MAD world and that they would avoid developing defenses against nuclear weapons. Instead, he argues that great powers would not be content to live in a MAD world and would try to search for ways to gain superiority over their nuclear rivals.

The United States was a strongly expansionist power in the Americas. Mearsheimer points to the comment made by Henry Cabot Lodge that the United States had a "record of conquest, colonization and territorial expansion unequaled by any people in the 19th century." In the 1840s, Europeans began speaking about the need to preserve a balance of power in America and contain further American expansion.

By 1900, however, the United States had achieved regional hegemony and in 1895 its Secretary of State Richard Olney told Britain's Lord Salisbury that "today the U.S. is practically sovereign on this continent and its fiat is law upon the subjects within its interposition...its infinite resources and isolated position render it master of the situation and practically invulnerable against all other powers."

On the penultimate page of Tragedy, Mearsheimer warns:

Neither Wilhelmine Germany, nor imperial Japan, nor Nazi Germany, nor the Soviet Union had nearly as much latent power as the United States had during their confrontations ... But if China were to become a giant Hong Kong, it would probably have somewhere on the order of four times as much latent power as the United States does, allowing China to gain a decisive military advantage over the United States.

One review held that rapprochement between Britain and the United States at the end of the 19th century and the success of the European Union in transforming Europe's geopolitical landscape cast serious doubt on the notion that balancing and destructive rivalry are inescapable features of international system. If Mearsheimer had analyzed episodes of lasting peace that defy the predictions of balance-of-power theory, he would perhaps have been less convinced of the pervasive logic of offensive realism.[9]

Another critique of Mearsheimer's views is that they ignore transnational superstructures, such as capitalism, non-state actors, and individual institutions within states. Mearsheimer asserts domestic politics to be irrelevant and states to be unable to provide one another with guarantees that they do not harbor hostile intentions. According to R. Harrison Wagner, Mearsheimer does not address whether democracy, trade, or another mechanism could prevent states from fighting, a view that is consistent with the broader perspective of the Kantian Peace Triangle.[10]

Mearsheimer argues that polarity in the international system is the cause of war. That is especially true in unbalanced multipolarity in which there is a potential hegemon. Balanced multipolarity in which there is no potential hegemon has a less-asymmetrical distribution of power and so is less feared.

The fear is the least in bipolarity in which there is usually a rough balance of power between the two major states. However, the bargaining model of war[11] disputes that claim on the grounds that war is costly. That and the fact that states are rational actors, requires some other cause that is more positive than polarity to drive nations to incur the cost of war.[12]

A collection of his critics’ academic essays[13] takes aim at Mearsheimer's theories in Tragedy: "Some of the criticism is scathing, proving that Mearsheimer is the political-science world's enfant terrible...."[14]

According to Richard Ned Lebow, "All of Mearsheimer’s predictions about the post-Cold War world have been wrong."[15]