What leads to war?

With wars raging in Ukraine and Gaza, and a looming USA-China conflict over Taiwan, one might ask what factors lead to war especially those that involve the great powers. There are a range of theories but the one that I find most compelling is that proposed by John J. Mearsheimer of the University of Chicago.

His theory, which is known in the literature as “offensive realism”, says that there are five determinants that drive nation state behaviour. First is that there is no higher authority than nation states in international politics. One might argue that today we have the United Nations and The International Court of Justice but in truth there is no global policeman. Secondly all nations have offensive military capabilities, although some can be very weak. Third, that nation states can never be certain of the true intentions of other states. Fourth, that states rank survival as their most important goal, amongst many others. And finally that states are rational actors in designing strategies to maximize their chances of survival, which is not to say they are not prone to misjudgements.

When combined, these factors cause states to behave so that they grow their power, with the ultimate aim to be the only great power in the system, or a hegemon.

Mearsheimer believes that no one country can achieve global hegemony. Rather they strive to be a regional hegemon and prevent other powers from becoming hegemons in their regions. In other words, the best way to survive and thrive in the international arena is to be the sole regional hegemon – a status that the United States currently holds following the collapse of the Soviet Union in 1989.

The USA achieved regional hegemony in the Americas by the end of the 19th Century primarily through land acquisitions from France, Britain and Russia, and conflicts with Spain and Mexico. Then there was the threat of the Monroe Doctrine of 1823 which put European powers on notice that any attempt to oppress any independent government on the American Continents would be viewed as “unfriendly disposition towards the United States.”

The United States has since worked hard to keep other great powers from becoming a hegemon in Europe or Asia. In the 20th Century it played a key role in thwarting the ambitions of four great powers that tried to become regional hegemons – Wilhelm’s Germany, Imperial Japan, Nazi Germany and the Soviet Union.

Which brings us to the rise of China. According to the logic of offensive realism, as China’s economic and military might continue to grow, it will attempt to dominate Asia the way the USA dominates the Western Hemisphere. If this theory is correct China will seek to maximize the power gap with its neighbors, in particular India, Japan and Russia, and to push the United States out of the Asia-Pacific region.

A rising China will also have strategic interests outside of Asia, just as the United States has beyond the Western Hemisphere. Particular areas of interest will be the Indian Ocean (especially the key maritime straits), the Persian Gulf and Africa.

The United States is likely to behave toward China largely the way it behaved toward the Soviet Union during the Cold War. This will involve containment to keep Beijing from using its military forces to conquer territory by forming a coalition with as many of China’s neighbors as possible. One recent example is the Quad alliance between USA, Japan, India and Australia.

But as China’s economy grows so does its latent power underpinned by a population more than four times greater than the United States, which suggests that it might be in the USA’s interest to attempt to engineer a dramatic slowdown in China’s growth.

Writing on this topic in 2014, Mearsheimer expected any Sino-American security competition to be categorized by a range of indicators including: major disputes, arms races and increased defence spending, support of proxy wars, government officials identifying each other as their number one threat, travel restrictions on visitors, barring of students studying certain subjects at American Universities, and export controls on some goods and services. If some of these sound familiar, it’s because they are already in play.

Although the presence of nuclear weapons on both sides creates a powerful incentive to avoid a major war as they did in the Cold War, the different geography and distribution of power in Asia compared to the Europe make a conventional war that does not escalate to nuclear exchange more likely between China and the United States.

Mearsheimer’s historic analysis of wars shows that when power is distributed amongst a number of great powers within a region, the likelihood of war goes up. During the Cold War we had the bipolarity of the Soviet Union /Warsaw Pact vs NATO. In Asia there is a multipolarity of great powers – China, Russia, Japan, a rising India. History shows that an ‘unbalanced multipolarity’ (one dominant power among many i.e China) has the most potential for war.

Mearsheimer goes on to rebut the counterarguments against the likelihood of war between USA and China. First is that China has embraced capitalism and as such it’s not the threat that communism posed during the Cold War. Mearsheimer counters that a different ideology, Nationalism, is a greater threat especially as it’s such a potent top-down and bottom-up phenomenon in contemporary China.

Secondly, there’s the claim that China’s Confucian culture means that China can rise peacefully. However there is little historic evidence that China has acted in accordance with the dictates of Confucianism. “Like liberalism in the United States, Confucianism makes it easy for China’s leaders to speak like idealists and act like realists”.

Finally, there’s the argument that the economic interdependence between China and USA makes war unlikely. Once again history shows that politics wins out over economics when nationalism affects the issue at stake. The large number of civil wars throughout history also supports the case of politics over prosperity. Strangely, there is ample historic precedents of war combatants continuing to maintain economic relations.

In summary, Mearsheimer makes a strong case that there is a high likelihood of a future war between China and USA. It is a bleak conclusion that we would prefer not to hear and may not agree with. Even so, it would be prudent to be prepared.


For a more detailed description of offensive realism, the validation of the theory against past history, and a more thorough exploration of the coming Sino-American conflict, I would recommend Mearsheimer’s book “The Tragedy of Great Power Politics” on which most of this article is based.


The writer is the co-author of Court of the Grandchildren, a novel set in 2050s America.

Main picture credit: Ri Butov via Pixabay

For more posts on this theme:

History! Read it and weep! – The transitions between dominant empires over the last five hundred years.

Every time history repeats the price goes up – Why societies collapse.

Eight lessons of history – The distillation from a lifelong study of human civilizations.

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