International peace and economic openness

Lane Kenworthy, The Good Society
April 2026

People are more likely to thrive when their society is safe from attack by external enemies and when it is able to interact economically with other societies. A nation’s government can shape, and to some degree control, what happens within its borders. But most countries — even those that follow the good-society playbook of liberalism, affluence, democratic political system, capitalist mixed economy, good universal K-12 education, expansive and generous public insurance programs, employment-friendly public services, moderate regulation of product markets and labor markets, strong labor unions or effective substitutes to ensure incomes rise in sync with the economy, and well-governed cities1 — need help when it comes to securing international peace and economic openness.

For most of human history, few cities or regions or countries could count on security from external attack. Armed conflict was commonplace. Since the middle of the 20th century, the story has been very different. Figure 1 shows the rate of deaths in armed conflicts involving at least one government. The data suggest a sharp drop since 1945, when World War II came to an end. For the world’s affluent longstanding-democratic countries, such deaths have been minimal and due almost entirely to “wars of choice” rather than ones in which they faced a direct attack or imminent threat.2

Figure 1. Deaths from armed conflicts
All countries. Deaths per 100,000 population. Armed conflicts involving at least one government. 1500-1945: Deaths from wars involving a “great power” — nations with a large population, economy, and military, such as the United States, China, the Soviet Union, Great Britain, Germany, France, Japan, Prussia, the Habsburg Empire. Data source: Steven Pinker, The Better Angels of Our Nature, 2011, figure 5.15. 1950ff: Deaths of combatants and civilians due to fighting in interstate, intrastate, and extrasystemic conflicts. Data source: Our World in Data, “Death in state-based conflict by region,” using data from the Uppsala Conflict Data Program, geoBoundaries, and the Peace Research Institute Oslo.

The world’s median-population country has around 10 million people, roughly the size of Sweden or Switzerland or the Chicago metro area. That’s too small to efficiently produce all of the goods and services people want, so trading with other countries is enormously beneficial. As we see in figure 2, trade between nations was minimal for most of human history. Since the middle of the 20th century it has increased quite significantly. That’s been true not just worldwide but in all of the rich democracies.3

Figure 2. Trade
All countries. Average of exports and imports as a share of GDP. Data sources: Our World in Data, “Trade and Globalization” and “Trade as a Share of GDP,” using data from Antoni Estevadeordal, Brian Frantz, and Alan M. Taylor, “The Rise and Fall of World Trade, 1870–1939,” Quarterly Journal of Economics, 2003 for 1500-1820, Mariko J. Klasing and Petros Milionis, “Quantifying the Evolution of World Trade, 1870-1949,” Journal of International Economics, 2014 for 1870-1949, Penn World Tables for 1950-69, and the OECD for 1970ff.

What has facilitated international peace and economic openness since the middle of the 20th century? Will it continue going forward?

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GOVERNMENT

Government plays a key role in ensuring peace and safety within a country. A centralized authority with a monopoly on the legitimate use of force can deter violence more effectively than other actors. The rise of governments is one of the main causes of the reduction in violence over the past millennium.4

But there is no world government. Instead we have 195 or so independent countries (“nation-states”). That’s how governments developed over time, and once in place they became difficult to dislodge. They could agree to subordinate their authority to that of a global government, as the American states did to a national government in the late 1700s. But they haven’t been willing to do so. One reason is that the most powerful nations aren’t the most populous ones, and in a one-person one-vote democratically-elected world government they would have considerably less sway. Another reason may be concern about whether a supranational government would have legitimacy and support among the citizenry, given that the nation is, at this point in history, the largest unit of solidarity to which people “feel an instinctive loyalty.”5 Another likely barrier is uncertainty. We have little evidence about how well a world government would work.6

Although less advantageous than a world government, nation-states are more conducive to peace and trade than what preceded them. A national government is a single entity that can speak on behalf of a country’s people, which makes negotiations more tractable and commitments more credible.7

The closest thing we have to a world government is the United Nations (UN). The UN was created in 1945, following the end of World War II. Its main body is the General Assembly, which consists of one representative from each of the world’s countries. Most votes require a simple majority to pass, though resolutions on defense and on the UN’s budget require two-thirds. However, only resolutions passed by the UN’s 15-member Security Council are binding on countries. Five of the Security Council members are permanent: the US, the United Kingdom, France, Russia, and China. Any one of these permanent members can veto a proposed Security Council resolution. The other 10 Security Council members rotate among countries, with a mechanism to ensure representation from each of the world’s regions.

The United Nations has the authority to impose peace on warring parties, and it has, on occasion, done so.8 In June 1950, North Korea invaded South Korea. The UN quickly authorized military force to resist the aggression, and a coalition of 20 nations led by the United States successfully expelled the North Koreans within four months. In August 1990, Iraq invaded Kuwait. The UN quickly issued a condemnation of the invasion. In November, the UN authorized the use of force by a US-led coalition if Iraq did not withdraw by January. By February that coalition had forced Iraq out of Kuwait.

However, the UN’s ability to impose peace is limited. The fact that any one of the Security Council’s permanent member countries can veto a resolution reduces the likelihood of UN action, particularly given that these nations have differing and sometimes directly conflicting interests. Worldwide there are about 30 million soldiers9; the UN’s armed force has only 75,000, and they are borrowed from member nations.

One of the UN’s most valuable contributions to peace is its monitoring role. After a conflict, UN representatives and troops can act “to verify that the terms of the peace agreement are kept: that the cease-fire holds; that any temporary cease-fire lines are respected; that troops are withdrawn or demobilized, if there are provisions to that effect.”10 These peacekeeping efforts reduce the number of people killed during the post-conflict period and decrease the likelihood that armed conflict resumes.11 The UN’s International Atomic Energy Agency (IAEA) inspects countries’ nuclear energy programs to ensure that nuclear fuel isn’t being diverted to produce nuclear weapons. The UN’s Human Rights Council (HRC) coordinates periodic reviews of countries’ human rights practices.

The United Nations clearly is a second-best mechanism for promoting world peace. But as one summary assessment puts it, “even an imperfect police force may be better than none. Although the international system has no central authority analogous to that of a well-governed domestic system, the institutions that have developed in its place have a beneficial — albeit imperfect and uneven — impact on world politics.”12

As peace and economic integration settled in among the countries of western Europe following the devastation of the two world wars, interest grew in the possibility of creating a supranational European governing body that could further reduce the likelihood of military conflict and enhance the ability to trade. In 1993, the European Union (EU) was officially established, and with it trade barriers between member nations were abolished. Despite the exit of the United Kingdom in 2016, the EU project has survived and expanded to include a number of central and eastern European countries.

POWER

In the absence of a supranational government, the relative economic and military power of individual countries, or alliances of countries, is likely to be critical for peace and trade.

A country with more military strength may be less averse to armed conflict than a country with less. Similarly, a nation with a larger economy, one less dependent on goods and services produced elsewhere, may be more likely to impose trade restrictions on others. On the other hand, if there is a single dominant nation — a “hegemon” — it may favor peace and trade and have the ability to impose that.

Great Britain was dominant militarily after its defeat of Napoleon in the early 1800s. Because Britain preferred peace among European countries, there was almost no intra-European war for a while. By the middle of the 1800s Britain also was dominant economically, and it began to push for freer trade. “Great Britain adopted free trade, permitting foreigners to sell anything to Britain without tax or restriction. More generally, from the 1860s until 1914, international trade among the principal industrialized nations was quite free.”13

Since the middle of the 20th century, the United States has had by far the largest economy and the most powerful military among the rich democratic countries. Its military spending has been the largest not only in an absolute sense but also, as we see in figure 3, as a share of its economy. It’s not too surprising, therefore, that the US during this era has been involved in more military conflicts than other affluent democracies.14 Because other rich democratic nations have perceived their military interests to be mostly aligned with those of the US, American military hegemony has allowed the others to spend less on their military and to be involved in fewer armed conflicts than might otherwise have been the case.

Figure 3. Military expenditures
Share of GDP. Data source: World Bank, “Military expenditure (% of GDP),” series MS.MIL.XPND.GD.ZS. Thick line: United States. “Asl” is Australia; “Aus” is Austria.

Because America’s population and economy are so large, it relies less on imports than do other countries, as we see in figure 4. This gives the US greater ability to behave selfishly when it comes to international trade agreements. However, for most of the period since the end of World War II, the US has done the opposite, promoting international economic cooperation and working to reduce barriers to trade.15 The US drove creation in 1947 of the General Agreement on Tariffs and Trade (GATT), which was superseded in 1995 by the World Trade Organization (WTO). These organizations have arranged negotiations among member countries aimed at reducing trade barriers. “While the WTO isn’t perfect … most WTO member states nonetheless accept that the WTO, like the GATT before it, facilitates international cooperation. It helps to set standards of behavior, verify compliance, ease joint decision making, and resolve disputes. The WTO makes available a great deal of information about trade and trade policies, and it monitors national compliance with international agreements.”16

Figure 4. Imports
Share of GDP. Data source: OECD Data Explorer, “Annual GDP and components — expenditure approach.” Thick line: United States. “Asl” is Australia; “Aus” is Austria.

From 1945 to 1990 the United States was much more powerful than other affluent capitalist democracies, but its military and economic power were matched by the Soviet Union and its allies. A balance of power such as this can be conducive to peace and trade. Where opposing countries or coalitions of countries have similar military or economic capabilities, they are more likely to agree, tacitly or formally, to patterns of behavior that are predictable and positive-sum rather than unpredictable and zero-sum.

The behavior of the first and second Trump administrations shows how unpredictable the international environment can be. The United States remains fairly hegemonic in both military and economic terms, and yet the Trump presidencies have pursued a more selfish approach to trade and military security than did previous American administrations.

So are peace and economic openness more likely when there is a hegemon or when there is a balance of power between a small number of countries or alliances? The answer seems to be “it depends.”

RULES AND NORMS

Given the lack of a supranational government, the rules that guide behavior between countries are created by countries themselves via formal agreements such as treaties.17

In 1864, a set of governments signed on to the first Geneva Convention, which specified rules for treatment of wounded soldiers. National governments may commit to not developing particular types of weapons (biological, nuclear) and to preventing non-signers from doing so. They can pledge to not attack each other militarily. They can promise to share information. They may agree to keep tariffs and other forms of trade restrictions at a low level. They can create organizations — the North Atlantic Treaty Organization (NATO), the World Trade Organization (WTO) — to monitor and enforce such agreements.

Because nations have limited ability to enforce rules, a key role in directing behavior is played by norms.18

For example, during the cold war era, from 1945 to 1990, the United States or the Soviet Union, the world’s two nuclear superpowers, could have required nearly any other country to do as it wished by threatening a nuclear attack. But for the most part they didn’t, in part because this would have been considered beyond the pale. Nor has any country actually used a nuclear weapon since 1945. The Eisenhower administration considered doing so to help French soldiers in Vietnam in 1954, but it backed away. “That countries do not use nuclear weapons for fear of retaliation is undoubtedly part of the explanation for this norm. But deterrence alone cannot explain the taboo: such weapons are not used even when the target does not have nuclear weapons or the capacity to retaliate against the user directly. Leaders appear reluctant to cross the nuclear threshold for fear of being branded as immoral, either personally or on behalf of their country.”19

Another example: after World War II the United States pushed a norm of territorial integrity — a country’s existing borders are sacrosanct and must be respected by other nations. This became broadly accepted, even where it made little sense and likely served as an obstacle to progress, as in postcolonial Africa.20

WHAT ELSE CAN HELP: AFFLUENCE, LIBERAL DEMOCRACY, TECHNOLOGY

Affluence

Rich nations are less likely to invade or militarily threaten other countries. One reason is that norms shift. When a society moves beyond scarcity conditions, people begin to place a higher priority on fairness, including nonviolent resolution of disputes.21

Another is that humans tend to be risk averse. A loss reduces our perceived wellbeing more than an equivalent gain boosts it, so we tend to try to avoid loss. When a society is richer, people have more to lose if their country engages in armed conflict.

A third reason is that affluence and commerce encourage us to see other people as an opportunity rather than a threat. We come to see interaction and integration as a source of potential gain rather than as a zero-sum game.22

The rise in affluence began in the 1800s, and the first societies to move beyond scarcity did so beginning in the mid-1900s. This has contributed to the growth in trade and the reduction in international violence since then.

Liberal democracy

Democratic governments are less likely to pursue war. The main reason is that democracy forces leaders to take into account what ordinary persons want. If the populace is less favorably inclined toward violent conflict than their leaders, their views may act as a brake on the enthusiasm for war.

An independent media, a key feature of modern liberal democracy, increases the amount of information available to citizens. This is likely to enhance the ability of citizens to influence policymakers’ decisions about armed conflict.

There also is a cultural element. Liberal democracy emphasizes that we frequently are wrong, and it fosters acceptance of diverse beliefs, preferences, and behaviors. It provides a context in which people with differing needs and wants can resolve their disagreements peaceably, in which disputes can be settled without resorting to physical force. It lowers the temperature of politics. A great service of liberal democratic politics, according to one observer, is “to enable people to live together when their views differ. Politics is a way of getting our ideas to brawl in place of our persons…. Politics, as opposed to pure power grabs, involves an acceptance of the truth that these conflicts can never be cured but only contained, and made as peaceable as humanly … possible. Politics is stress. The objective of practicing it should be to keep the stress from turning into cardiac arrest.”23 This orientation is likely to seep over from domestic politics into international ones.

Do liberal democratic governments tend to be militarily inferior to authoritarian ones? That hasn’t been the case historically, partly because liberal democracy, when complemented by a market-based economy, has proved conducive to innovation and technological advance. In addition, liberal democracy creates incentive and opportunity to identify errors and correct them, so a government is less likely to make calamitous mistakes.24

Since the late 1700s, democracy has been slowly but steadily spreading across the globe.25 This has contributed to a reduction in violence between countries. There are hardly any clear cases of war between democratic countries.26 The armed conflict democracies have been involved in are of three main types: (1) colonial expansion by some democratic European nations, particularly Great Britain, in the late 1800s (2) the two world wars, both initiated by non-democratic governments (Germany in World War I and Germany, Italy, and Japan in World War II); (3) Cold War interventions by the United States.

The effect of democracy on trade is less straightforward. Trade is, on the whole, beneficial for people in virtually every country. Yet a significant share of the population may not believe this. And particular groups that benefit from protectionism may care more passionately about this issue and hence lobby more forcefully than those who favor freer trade.27

Technology

Technological advances have been central to the rise of trade. More efficient energy, mass production of goods, faster and cheaper transportation of those goods, enhanced communication, and better collection and analysis of data have made it easier and more lucrative to export and import goods and services.

In the military arena, technological advances in weaponry have increased the destruction and lethality of war. Yet there also are ways in which they have helped to reduce the incidence of armed conflict. Nuclear weapons reduce war because the potential magnitude of loss is massive.28 Rocket launchers and drones reduce war by reducing the military value of territory and hence the desire of countries to invade others in order to gain territory. Satellites increase information about the other side’s intentions and capabilities. Video technology allows negotiators to communicate face-to-face even when they can’t be in the same location.

PEACE AND TRADE ARE MUTUALLY REINFORCING

People benefit from international peace and from international trade. Happily, these two good things tend to be complementary.

Trade is conducive to peace. Trade with other countries improves our ability to get goods and services via exchange rather than conquest, which in turn encourages us to think of them as a source of economic gain rather than as a threat. Empirically, nations that trade with one another are less likely to attack one another.29

And peace facilitates trade. It reduces the cost and risk of cross-border economic exchange. It’s not mere coincidence that international trade has flourished in the era since 1945 when international armed conflict has been at a historic low (figures 1 and 2 above).

NEW THREATS

Since 1945, the “liberal international order”30 has for the most part given affluent democratic nations, and many others too, exactly what they need from the international environment: peace and economic openness.

Will this continue? Some observers are pessimistic31:

During the past seven decades, as a percent of the population, fewer people have died in fewer wars and fewer occupations and fewer famines and fewer disease outbreaks than since the dawn of recorded history. Historically speaking, we live in an embarrassment of riches and peace. All of these evolutions and more are tightly interwoven. Inseparable. But there is a simple fact that is often overlooked. They are artificial. We have been living in a perfect moment. And it is passing. The world of the past few decades has been the best it will ever be in our lifetime. Instead of cheap and better and faster, we’re rapidly transitioning into a world that’s pricier and worse and slower. Because the world — our world — is breaking apart….

The Americans emerged from World War II financially strong and with the only remaining navy of any substance…. The Americans would ensure that all countries on all continents would enjoy full access to the global ocean. What had once been a highly contested strategic environment transformed into a single, global, safe, functionally internal waterway filled and supplied by diesel-powered steel behemoths. The technologies developed during the previous couple of centuries would finally be allowed to function without the specter of war (or, more to the point, the Americans would handle said specter). No privateering. No piracy. No imperial confiscations…. While the Industrial Revolution made it much cheaper to ship products from A to B, it took the Americans’ global Order to make transport much safer. Between the changed technological base and the changed geopolitical circumstances, what constitutes a Geography of Success expanded to almost everywhere…. Some 80 percent of global trade by volume and 70 percent by value is transported by oceangoing vessels….

The world we know is eminently fragile. And that’s when it is working to design. Today’s economic landscape isn’t so much dependent upon as it is eminently addicted to American strategic and tactical overwatch. Remove the Americans, and long-haul shipping degrades from being the norm to being the exception….

The American political system has turned sharply insular and America simply is not going to be keeping the world open for trade….

The 2020s will see a collapse of consumption and production and investment and trade almost everywhere. Globalization will shatter into pieces. Some regional. Some national. Some smaller. It will be costly. It will make life slower. And above all, worse.

There are indeed worrying developments.

Donald Trump was elected US president in 2016 and 2024 in part on a promise to increase tariffs in order to bring manufacturing jobs back to the United States and reduce the country’s trade deficit. The average effective tariff rate on imports into the US was 2% in the years preceding Trump. During his first term that increased to about 3%, as we see in figure 5. The Biden administration kept it at 3%. In the early years of his second term, Trump’s tariff increases were larger. In 2025 and 2026 the average rate jumped to 8%, a level not seen for more than half a century.

Figure 5. US tariff rate
Average effective tariff rate (customs duty revenue as a share of goods imports). Data source: Yale Budget Lab, “State of U.S. Tariffs.”

Trump has also reoriented US foreign policy. After campaigning in favor of staying out of foreign affairs, Trump in his second term has already launched military attacks, incursions, or kidnappings targeting seven countries (Somalia, Iraq, Yemen, Caribbean territories, Syria, Venezuela, and Iran), threatened to annex Canada and to take Greenland by force, and relentlessly criticized the elected leaders of fellow NATO member countries. The US military attack on Iran in early 2026 has resulted in a significant reduction in the supply of oil, which could, depending on how long it lasts and how well or poorly countries are able to adjust, cause a significant economic downturn.

Trump isn’t the only cause of disruption to trade and peace in recent years. Russia’s invasion of Ukraine in 2022 and China’s emergence as a rival military and economic superpower have begun to change the interests and strategies of policymakers in affluent democratic nations. The Biden administration, for example, moved aggressively to bring manufacture of advanced semiconductor chips back to the United States, worried about a possible Chinese military attack on Taiwan, where a large portion of those chips are made. Western European policymakers have attempted to speed up their transition to clean energy in order to reduce dependence on Russian natural gas.

The disruption of global supply chains caused by the Covid pandemic in 2020-22 turned out to be a significant but temporary problem for most rich-world economies. Yet it has raised concerns about economic resilience in the event of a deeper or lengthier crisis.

So there clearly are threats to international peace and economic openness. And yet, thus far the system has held up. Ukraine has battled Russia to a stalemate. Apart from the US, no affluent democracy has launched, joined, or been pulled into an armed conflict. Trade in goods hasn’t decreased, in part because most other countries have chosen to not retaliate against America’s tariff increases.32 And in early 2026 the US Supreme Court ruled most of those increases illegal.

It’s early days for what might turn out to be a new and far less beneficial international order. But so far there are grounds for guarded optimism.

  1. Lane Kenworthy, “Liberalism,” The Good Society; Kenworthy, “Affluence and Progress,” The Good Society; Kenworthy, “Social Democratic Capitalism,” The Good Society; Kenworthy, “How to Ensure Rising Incomes When Labor Unions Are Weak,” The Good Society; Kenworthy and Joel Rogers, “The Good City in the Good Society.” ↩︎
  2. Wars of choice: US anti-Soviet bloc preemptive wars (Korea, Vietnam); US Middle East order/control/oil wars (Persian Gulf, Afghanistan, Iraq, Libya, ISIS/Syria, Iran); European military efforts to suppress anti-colonial independence movements (Belgium in Congo, France in Algeria and Vietnam, the Netherlands in Indonesia, Portugal in Angola and Mozambique, United Kingdom in Kenya). ↩︎
  3. Lane Kenworthy, “Trade,” The Good Society. ↩︎
  4. Lane Kenworthy, “Safety,” The Good Society. ↩︎
  5. Francis Fukuyama, Liberalism and Its Discontents, Farrar, Straus, and Giroux, 2022, p. 132. ↩︎
  6. As Fukuyama puts it: “The fact that nations remain the locus of coercive power should make us cautious about proposals to create new supranational bodies and to delegate such power to them. We have several hundred years of experience in learning how to constrain power at a national level through legal and legislative institutions, and how to balance power such that its use reflects general interests. We have no idea how to create such institutions at a global level.” Fukuyama, Liberalism and Its Discontents, pp. 131-132. ↩︎
  7. G. John Ikenberry, A World Safe for Democracy: Liberal Internationalism and the Crises of Global Order, Yale University Press, 2020; Jeffry A. Frieden, David A. Lake, and Kenneth A. Schultz, World Politics: Interests, Interactions, Institutions, 5th edition, W.W. Norton, 2022. ↩︎
  8. Frieden, Lake, and Schultz, World Politics, ch. 5. ↩︎
  9. World Bank, “Armed forces personnel, total.” ↩︎
  10. Frieden, Lake, and Schultz, World Politics, p. 573. ↩︎
  11. Frieden, Lake, and Schultz, World Politics, pp. 597-598 ↩︎
  12. Frieden, Lake, and Schultz, World Politics, p. 609. ↩︎
  13. Frieden, Lake, and Schultz, World Politics, p. 766; Ikenberry, A World Safe for Democracy, ch. 2. ↩︎
  14. Wikipedia, “Lists of Wars Involving the United States.” ↩︎
  15. Ikenberry, A World Safe for Democracy; Frieden, Lake, and Schultz, World Politics. ↩︎
  16. Frieden, Lake, and Schultz, World Politics, pp. 828-829. ↩︎
  17. Ikenberry, A World Safe for Democracy; Frieden, Lake, and Schultz, World Politics. ↩︎
  18. Ikenberry, A World Safe for Democracy; Frieden, Lake, and Schultz, World Politics. ↩︎
  19. Frieden, Lake, and Schultz, World Politics, pp. 1177-1178. ↩︎
  20. Joe Studwell, How Africa Works, Atlantic Monthly Press, 2026. ↩︎
  21. Kenworthy, “Affluence and Progress.” ↩︎
  22. Steven Pinker, The Better Angels of Our Nature: Why Violence Has Declined, Viking, 2011. ↩︎
  23. Adam Gopnik, “Can’t We Come Up with Something Better Than Liberal Democracy?,” The New Yorker, 2022. ↩︎
  24. Paul Starr, Freedom’s Power: The True Force of Liberalism, Basic Books, 2007; Adam Gopnik, A Thousand Small Sanities: The Moral Adventure of Liberalism, Basic Books, 2019. ↩︎
  25. Lane Kenworthy, “Democracy,” The Good Society. ↩︎
  26. Frieden, Lake, and Schultz, World Politics, p. 380. ↩︎
  27. Frieden, Lake, and Schultz, World Politics, ch. 7. ↩︎
  28. Frieden, Lake, and Schultz, World Politics, p. 378. ↩︎
  29. Frieden, Lake, and Schultz, World Politics, ch. 7; Ling Feng, Qiuyue Huang, Zhiyuan Li, and Christopher M. Meissner, “The ‘Peace Dividend’ of International Trade: A New Empirical Approach,” Working Paper 35078, National Bureau of Economic Research, 2026. ↩︎
  30. Lane Kenworthy, “Liberalism, Liberal Democracy, and the Liberal International Order,” The Good Society. ↩︎
  31. Peter Zeihan, The End of the World Is Just the Beginning: Mapping the Collapse of Globalization, HarperCollins, 2022, pp. 1, 83, 134, 139, 123-124, 3-4. ↩︎
  32. The Economist, “Why Donald Trump’s Tariffs Are Failing to Break Global Trade,” October 8, 2025; Martin Wolf, “The Global Economy Turns Out to Be More Resilient Than We Had Feared,” Financial Times, March 31, 2026. ↩︎