Wars between countries are among the greatest threats to world order. Throughout history, they have killed tens of millions of people, displaced entire communities, caused trillions of dollars in destruction, and contributed to the spread of hunger, poverty, and disease.

It thus comes as welcome news that such costly interstate wars have been on the decline since the end of World War II. However, this trend does not mean that countries peacefully coexist or that the threat of full-scale war has disappeared.

This lesson explains the decline in interstate war, breaks down the ways in which countries continue to come into conflict, and explores how two of the world’s most powerful countries—the United States and China—are sliding into conflict without having fired a single bullet.

Why has interstate war become less common?

For one, the potential devastation of war has increased since the introduction of nuclear weapons at the end of World War II. Nuclear-armed powers launching a full-scale war today could spell the end of civilization itself.

Further, powerful alliances like the North Atlantic Treaty Organization serve as credible deterrents to interstate war, and international institutions such as the United Nations provide forums for countries to resolve disputes without resorting to fighting.

Some political scientists attribute this trend to the worldwide increase in the number of democracies, arguing that accountable leaders are less willing to make potentially costly and unpopular decisions like going to war. Other experts believe that an increase in international trade has made the world a safer place, as economically interdependent countries are less likely to go to war. 

What kinds of interstate conflict persist?

The world is far from a harmonious place, and countries continue to try to increase their power, undermine their rivals, and advance their national interests. In some cases, violent interstate conflict occurs but stops short of an all-out war. In other instances, countries battle for influence through a range of economic, diplomatic, and cyber tools. Though these forms of interstate conflict can be less violent than conventional war, they still pose considerable risks to people and their governments.

Types of Interstate Conflict

Click on a type to learn more about it.

How are the United States and China in conflict?

Even if not at war, the United States is in conflict with various countries. It levies sanctions against Cuba, Iran, and North Korea, bears the brunt of election interference from Iran and Russia, and backs opponents of Syrian President Bashar al-Assad and Venezuelan President Nicolás Maduro. The United States and China have not directly fought each other since the Korean War, but the world’s two largest economies have come into conflict in several costly ways.

The two countries are embroiled in a trade war, with the United States accusing China of stealing intellectual property from American companies and violating the commitments it made when it joined the World Trade Organization (WTO). Similarly, China accuses the United States of not upholding its own WTO commitments. Since 2018, the United States has imposed tariffs on a wide variety of Chinese goods, and China retaliated with tariffs of its own. As a result, goods are more expensive for consumers in both countries, while exporters have been harmed. 

The trade war is closely related to escalating technology competition between the two countries. Citing national security risks, the United States banned China’s largest telecommunications company, Huawei, from building 5G wireless networks in the United States and announced sanctions on foreign companies that sell certain technology to Huawei. The United States has similarly cited national security concerns in attempting to ban popular Chinese-owned applications like TikTok and WeChat. Meanwhile, China has prohibited large U.S. technology companies—including Facebook, Google, and Twitter—from operating in China given their potential to enable political dissent and instability.

In 2020, the United States also placed economic sanctions on Chinese companies and political leaders linked to human rights violations in China’s Xinjiang region, where the Chinese government has detained over one million ethnic Uighurs and other Muslim minorities in so-called reeducation camps. Those sanctions restrict targeted companies from buying American technology and ban several senior officials and their families from entering the United States or accessing assets they own in the country.

The United States and China have also traded accusations of meddling in the other’s domestic affairs. China claims the United States is destabilizing the political situation in Hong Kong by supporting pro-democracy protesters. The United States, meanwhile, has accused China of repeatedly attempting to influence U.S. elections.

Additionally, members of the Chinese military have carried out cyberattacks on U.S. government agencies and companies. In a 2017 attack on the American credit agency Equifax, hackers stole the social security numbers of over 145 million Americans. Concerns about escalating cyberwarfare boiled over into a diplomatic conflict in 2020 when the United States ordered China to close its consulate in Houston over allegations of Chinese diplomats spying and aiding in the theft of U.S. intellectual property. In retaliation, China shuttered the U.S. consulate in Chengdu, cutting off U.S. access to nearby Tibet, where the United States has long accused China of human rights violations.

None of these issues has devolved into all-out war, but the world’s two most powerful economies locked in conflict has serious implications for world order and hundreds of billions of dollars in trade. Further, the increasing tensions that come with each instance of economic, political, cyber, and diplomatic conflict raise the likelihood that some flash point could become the tipping point for war. Any Chinese aggression against Taiwan (a democratic self-ruling island that China claims as its own), in the South China Sea (an area where China’s expansive claims to islands conflict with those of U.S. allies), or in the Senkaku Islands (which China claims but the United States recognizes as Japanese territory) could lead the two global powers into a far more violent stage in their ongoing rivalry.

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