Vladimir Putin is a keen reader of history. In long months of isolation during the covid-19 pandemic, say some, Russia’s president lingered in the Kremlin archives brooding over his country’s past as a great power and dreaming of restoring it. He admires the early Romanovs, who cemented their rule at the turn of the 17th century following a dynastic crisis marked by violence and lawlessness in Russia and then set off conquering their way to the Pacific Ocean. In particular he has compared himself to Peter the Great, the tsar who seized land from Sweden and turned Russia into the dominant power in the Baltic region.
In 2014 Mr Putin’s forces seized Crimea, a peninsula in southern Ukraine. People there were eventually handed Russian passports. At the time, the move seemed simply opportunistic. Conquering Crimea was popular among Russians, many of whom considered the territory’s transfer from the Russian Soviet Federation of Socialist Republics to the Ukrainian Soviet Socialist Republic in 1954 as illegitimate. But the taking of Crimea, and the support provided by Russia to rebels in Ukraine’s Luhansk and Donetsk provinces, now look more like steps in a grand plan to seize Ukrainian land.
In a rambling speech three days before Russian missiles started falling on Ukrainian cities in February, Mr Putin lamented the loss of the “territory of the former Russian empire”. Eight months into the invasion his forces now occupy some 15% of Ukrainian soil. But it is not going according to plan. Ukraine’s counter-offensive continues to push back Russian troops. On September 30th, following sham referendums, Russia announced it had annexed four eastern and southern regions of Ukraine, though it does not wholly control them. Announcing the move, Mr Putin decried the West’s “fake rules”, including the inviolability of borders. But his invasion has weakened Russia, not strengthened it. In attempting to conquer a neighbouring sovereign country, he tried bucking history. He is failing.
Since the end of the second world war, wars between countries have, for many reasons, become rarer. That is not to say they have disappeared, and the decline in interstate war is not the same as peace: civil wars (such as the one now raging in Ethiopia), state repression and other mass violence continue to inflict enormous human suffering. Wars of independence from colonial repression were often extremely deadly too. But examples of one state sending its armed forces over a border to fight those of another have become far less common.
Even rarer than war between countries, however, is what Mr Putin is trying to do: imperial conquest, or invading a country to make its territory his own. As Yuval Noah Harari, a historian and author, wrote this year, “most governments stopped seeing wars of aggression as an acceptable tool to advance their interests, and most nations stopped fantasising about conquering and annexing their neighbours.” Saddam Hussein believed, wrongly, that Iraq would be permitted by other states to swallow up Kuwait in 1990. Most other examples of such efforts—such as India absorbing Goa in 1961 and Sikkim in 1975—are older still. China might yet try it in Taiwan. But with the exception of Mr Putin’s efforts, and clashes over uninhabited border areas or small islands, the phenomenon has all but disappeared.
The dramatic decline did not happen by chance. The reasons behind it explain something about how states now interact with each other. They also point to why Mr Putin’s war of aggression in Ukraine is so exceptional, and unlikely to end in success.

Battle deaths in conflicts between states, per 100,000 world population

20

15

10

Ukraine war, total

estimated deaths*

High 50,000

Low 16,500

5

0

1946

50

55

60

65

70

75

80

85

90

95

2000

05

10

15

22

*To August 1st 2022

Evidence for the decline in war is not hard to find. The Correlates of War Project, an international research outfit, has collected data on every interstate war fought since 1816, after the Napoleonic wars. These data confirm that wars—meaning conflicts between states with at least 1,000 battle deaths in one year—are becoming much rarer.
The causes are many. Where economies rely on international trade which can be disrupted by conflict, the cost of war increases. In turn, lower trade barriers help to reduce the potential spoils. After all, invading territory in order to impose trade terms, or to access new markets, is hardly rewarding if markets were already open. This is not a sufficient condition for peace, as the first world war showed, but it does reduce the incentives for conflict. War is also rare between democracies (the number of which has increased in the past 200 years), perhaps because voters tend not to like the costs of it and boot out their belligerent leaders. Some scholars even argue that, depending on how strictly you define democracy, two have never gone to war with each other. Finally, strategic nuclear weapons would make total war so destructive as to be hard to imagine.
Smaller conflicts remain common, but even counting all interstate clashes with over 25 deaths, the proportion of the world’s population killed in battle has sharply declined (see chart). This is in part because improved training and equipment protect soldiers better than ever, and medicine has improved. Researchers estimate the wounded-to-killed ratio in wars has more than doubled over the past 50 years.
In Ukraine, however, the human cost has already been extraordinarily high. Estimates vary, but at least 16,500 soldiers have died from both sides, and that number may be as high as 50,000. In September Ben Wallace, Britain’s defence minister, claimed that Russian casualties (the dead and the wounded) amounted to 80,000.

Number of territorial changes, by decade surrounding

Independence or other processes

80

Part of territory given to other country

Unification or secession

Annexation

60

40

20

Conquest

0

1820

40

60

80

1900

20

40

60

80

2000

2015

Conquests, by country gaining territory

Attempts to conquer

Ukrainian territory

Crimea (2014) and

Eastern Ukraine (2022)

Area gained, sq km

0.5m

1.5m

2.5m

Russia

Japan

Italy

France

Britain

Ottoman

Empire

Other

1820

40

60

80

1900

20

40

60

80

2000

22

As a big and deadly war, Mr Putin’s invasion of Ukraine looks unusual when compared with historical trends. But his aim, to use force to permanently enlarge his country’s already immense territory, is not just a rarity. It is an aberration. According to the Correlates of War data, since the late 1970s no large conquests took place until the seizing of Crimea in 2014. Attempted conquests have steadily declined too: in data going back to the first world war collected by Dan Altman, a researcher, violent bids for territory have fallen from roughly one a year to almost none, if small islands and unpopulated areas are excluded.
In a typical decade between 1850 and 1940, perhaps 1% of the world’s population saw their rulers change as a result of conquest, according to the Correlates of War data. But in the past 40 years, excluding Ukraine, fewer than 100,000 people (or 0.001%) have experienced the same, almost all of them in long-disputed areas during the war between Armenia and Azerbaijan in 2020.
A variety of factors explain the almost complete elimination of states successfully seizing each others’ territory. The economic benefits have shrivelled while the costs have become extraordinarily high; the modern expectations of a state make it difficult to rule a group of people against its will; and international norms and institutions mean that other states are more likely to intervene to prevent it.

Six-day war

1967

Even if the destructive force of a modern war doesn’t destroy an area’s productive potential, economic activity, once driven almost entirely by land and natural resources, is now more reliant on human capital. Workers are unlikely to toil in conflict zones, or under the control of invaders. If they can, they will often leave. The security measures often required to maintain control over territory require restrictions on movement and trade that can sap its growth.
Take the West Bank, seized by Israel during the six-day war against Arab states in 1967. In the decades since, Israel has built scores of settlements, both in an arc around East Jerusalem, which it formally annexed in 1980, and more widely across the West Bank. Today around 60% of the area is under full Israeli control; the rest is either under joint Israeli and Palestinian jurisdiction or controlled mostly by the Palestinian Authority overseen by Israel.
Some Israeli politicians accept that most of the West Bank would be the core of a Palestinian state in a future peace deal, others want to annex it fully. But in the meantime it has withered. According to the UN, the GDP per person of the West Bank and the Gaza strip, also captured by Israel during the six-day war, was just $3,700 in 2019, compared with $44,000 for Israel. Gaza proved so tricky to keep under control that Israel withdrew its last 8,500 settlers in 2005.
Carl Kaysen, who served as deputy national security adviser to President John F. Kennedy and taught at the Massachusetts Institute of Technology, questioned in 1990 whether a conquered industrialised society could ever be fully incorporated into a modern state against the will of its inhabitants. The population needs to be won over. People can sometimes be exploited economically. Peter Liberman, of the City University of New York, has pointed to Japan, which seized Korea, Manchuria and Taiwan between 1895 and 1931 and built an “economically booming and politically submissive empire”. But this was only possible using enormous brutality, and under obvious military control.
Globalisation has eroded the incentives to conquer too. A vast reduction in shipping costs over the past century has allowed countries to look far beyond their neighbours for a greater share of trade and resources. And, as tariffs and other barriers to trade between countries have fallen, it has become pointless to integrate markets by force.

Afghanistan

2001

Those attempting to hold territory face increased challenges. America and its allies found as much in their efforts to turn impoverished Afghanistan into a modern democracy after they invaded and deposed the Taliban in 2001.
Despite the occupiers’ overwhelming military advantages—such as control of the skies—Taliban forces eventually triumphed, resulting in a humiliating withdrawal for America in 2021. Highly motivated guerilla fighters, often supported by a sympathetic civilian population, were far readier to suffer casualties and privation than were the occupiers. Neighbouring Pakistan, whose army and spies long backed the Taliban, badly complicated America’s efforts to impose order. The extraordinary costs of sustaining a military occupation in a remote, land-locked territory in Asia, meanwhile, became ever harder for American politicians to explain to voters.
In part, this is because expectations on what states need to provide their citizens have grown, be it education, health care or economic opportunities. That increases costs (and the need for revenue), and introduces points of friction between citizens and the state, such as schooling. In many countries, people also have clearer national identities than they once did. Primary education, which plays an important role in instilling such identities in children, especially through language learning, is a frequent source of conflict in occupied areas. Stable borders play a role in building national identities too, solidifying them over the decades. In Ukraine, even predominantly Russian-speaking parts of the east and south have become vehemently anti-Russian. In Odessa, a port city which holds a treasured place in Russia’s history and culture, Ukrainian flags now fly from every street corner.
And options for controlling the occupied, at least for conquerors with a conscience—or the desire to look like they have one—are more limited than they once were. Slavery and “divide and rule” tactics, like those Britain used to maintain order in the empire, are now held as morally bankrupt and barbaric almost everywhere (even if they remain far from wholly eliminated). Genocide is even more so—to the point outside states perceive a responsibility, and right, to protect populations from it, using military means if need be.

Kuwait

1990

It is not just atrocities such as genocide that will prompt other states to intervene and stop an occupation. On August 2nd 1990, Iraqi forces moved into Kuwait. Less than four weeks later Saddam Hussein announced that Kuwait had become the 19th governorate of Iraq. The reaction from the rest of the world was swift. A day after the invasion the UN Security Council unanimously passed resolution 660, condemning it. Even Russia and China were happy to sign up to an American-led intervention against Saddam. Eleven more resolutions followed and, after Saddam ignored several deadlines to withdraw, Operation Desert Storm began. A coalition of 35 countries routed the Iraqi army in just six weeks.
The first Gulf War happened at a time of American supremacy at the end of the Cold War, and is the clearest recent example of the norm against conquest being enforced. By and large, public opinion no longer holds conquest to be a legitimate tool of statecraft, which influences how leaders act. It also limits conquest in other ways. Customary behaviour, or the adherence to norms, is one source of international law. And multilateral institutions such as the UN give these norms power by upholding them.
The establishment of a consensus against big land grabs is part of why so few countries have expanded their borders by force since the end of the second world war, including in places where few expected borders to be stable, such as in newly independent parts of Africa. Although Moroccan and Mauritanian soldiers invaded Western Sahara in 1975, other more recent border changes in the continent have been the result of secession (as in Eritrea and South Sudan) not conquest. Norms and institutions may not preclude states from attempting conquest. But public attitudes, international law and institutions make them even less likely to succeed.
Empire state of mind
Mr Putin has long been blind to these arguments. And he cares little for others’ interpretation of the past. “People with their own views on our country’s history might argue with me, but I think that the Russian and Ukrainian peoples are practically one single people, no matter what others might say,” he declared in 2014, less than six months after he seized Crimea. Perhaps comments like these should have alerted Western powers to his wider territorial ambitions in Ukraine much sooner.
But now that they have woken up, they seem determined to uphold the norms that have halted other countries from expanding their borders by force. Western countries have not sent their forces to fight in Ukraine. But they are supplying Ukraine with their most advanced conventional weapons, training its soldiers, funding its government, and attempting to cripple Mr Putin’s invasion with sanctions. On the 21st September, in a speech to the UN General Assembly, President Joe Biden put it bluntly: “If nations can pursue their imperial ambitions without consequences, then we put at risk everything this very institution stands for.”
Correction (October 25th): A previous version of this article misstated the number of interstate wars since 1992 with over 1,000 deaths. Sorry.
The data and code to replicate this analysis can be found here.

Chart sources: Correlates of War Project; Our World In Data; World Bank; news reports, The Economist

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