On 1 December 1925, the Locarno Treaties were signed by Germany, France, Great Britain, Belgium and Italy, with some of the additional treaties also including Poland and Czechoslovakia as signatories. Negotiated in Switzerland in October, the final signing was in London at the Foreign Office. A consequence of the post-World War One settlements of the Peace of Paris, which saw extensive territorial changes, these agreements were intended to fix the boundaries between Germany and neighbouring states.

As Treaty of Mutual Guarantee of 16 October 1925 said, after a preamble which invoked the “the scourge of the war of 1914-1918”:

The High Contracting Parties collectively and severally guarantee, in the manner provided in the following Articles, the maintenance of the territorial status quo resulting from the frontiers between Germany and Belgium and between Germany and France, and the inviolability of the said frontiers as fixed by or in pursuance of the Treaty of Peace signed at Versailles on June 28, 1919, and also the observance of the stipulations of Articles 42 and 43 of the said treaty concerning the demilitarised zone (Article 1).

(The demilitarised zone here was land “either on the left bank of the Rhine or on the right bank to the west of a line drawn 50 kilometres to the East of the Rhine”, an area often called the Rhineland, to provide a buffer zone between Germany and France.)

The “territorial status quo” sounds a worthy aspiration, but at the time this was an important innovation. We have, I think, a somewhat distorted collective memory, thinking that most boundaries are fixed and have been for a long time. But many Western European borders, not to mention those in Central and Eastern Europe, the Middle East, and other parts of the world, are much more recent.

In my 2013 book The Birth of Territory, I traced the emergence of the idea that a political actor would have exclusive power within the territory they claimed. The idea that the King was an Emperor in his kingdom was something which emerged in the late Middle Ages, and was used in jurisdictional disputes between cities, princes, kings, emperors and popes. Over time, this became recoded as the relation between sovereignty and territory. Jean Gottmann described territory as “the spatial extent of sovereignty” (The Significance of Territory, p. 49), a phrase I used as the subtitle of my 2009 book Terror and Territory.

But the idea that the king’s power, or a state’s sovereignty, was exercised within borders which were fixed was largely unknown at this time. Kings believed they could gain more land, states could accumulate more territory. This could be in a range of ways, including marriage alliances, inheritance, purchase, colonisation, conquest, or punishment of a defeated state. The Louisiana Purchase of the early 19^th century and the Alaska purchase of 1863 are of course well known. Territorial conquest continued into the twentieth century, and the punitive settlement imposed on the defeated powers of Germany, Austria-Hungary and the Ottoman Empire after World War One was part of what the Locarno Treaties were aiming to secure.

The Locarno Pact was important in stressing the fixity of borders, the territorial status quo. Today we think of this as territorial integrity, the idea that as well as a state being sovereign within its borders, those borders are fixed. States are not supposed to seize parts of their neighbours’ territories, nor promote secessionist claims within them. The United Nations Charter is categorical about this: “All Members shall refrain in their international relations from the threat or use of force against the territorial integrity or political independence of any state, or in any other manner inconsistent with the Purposes of the United Nations” (Article 2, clause 4). Territorial integrity is usually meant in the sense of territorial preservation, but it also means territorial sovereignty – not just that the borders remain fixed, but that a state can exercise its sovereignty within them. But as my historical work tried to show, those two aspects have very different histories, which come together only in the twentieth century. In territorial preservation, the fixity of borders, Locarno has an important place.

The Locarno Pact was also important in the signatories agreeing that states should handle disputes through negotiation and the framework of the League of Nations. The Treaty of Mutual Guarantee stressed that Germany and Belgium, and Germany and France, “will in no case attack or invade each other or resort to war against each other”, except in self-defence, or if authorised by the League (Article 2). Articles 3 to 5 stressed the peaceful means of dispute resolution. Germany was admitted to the League of Nations in 1926 as a consequence. Building on these agreements, the Kellogg-Briand Pact of 1928 said that states would “condemn recourse to war for the solution of international controversies, and renounce it, as an instrument of national policy in their relations with one another”. It was initially signed between France, Germany and the United States, with other signatories following. These two pacts and the League of Nations were part of attempts in the 1920s to secure Western Europe from another devastating war.

The Locarno Pact did not last for long. Negotiations to secure Germany’s Eastern borders – the so-called Eastern Locarno – failed. The grievances of the Treaty of Versailles – the part of the Peace of Paris which treated Germany – endured, and many German politicians wanted its terms, including the territorial ones, reversed. The history of Germany’s territorial claims in the 1930s, from the remilitarisation of the Rhineland to the Anschluss with Austria, and the claims on the Sudetenland through to the rest of Czechoslovakia and Poland, is well known. Of course, the territorial claims made did not end there, either.

The Locarno Treaties could therefore be seen, along with the League of Nations, as a failure. In fundamental aspects they were, since Germany’s western borders were not settled by the agreements and were only reimposed by force after World War Two. Germany’s eastern borders went through further changes at the end of that war, and of course it was occupied and then divided until 1990 and reunification. The Kellogg-Briand Pact could be seen as another failure, but it was part of the legal case of the Nuremberg trials and the Tokyo War Crimes Tribunal after World War Two ended.

Similarly, the Locarno Treaties did help to get this idea of the fixity of borders onto the international agenda, after some 19^th century colonial developments, discussed by Kerry Goettlich in “Territorial Integrity as an Etiquette of Thieves”. The aspirations were behind some of thinking of the framing of the United Nations Charter. Since the founding of the United Nations, the attempt of the international community has been, again and again, to preserve existing boundaries. Decolonisation in Africa broadly took place with the independent states keeping the boundaries of their colonial era, either the boundaries between colonising powers, or divisions within European empires. The Cairo declaration of the Organisation of African Unity in 1964 recognised both that “border problems constitute a grave and permanent factor of dissention”, and that “the borders of African States, on the day of their independence, constitute a tangible reality”. The signatories therefore “pledge themselves to respect the borders existing on their achievement of national independence”. This was a process which had earlier been followed in South America, sometimes discussed through the legal notion of uti possidetis, that what you have you will continue to possess.There are exceptions of course, though they tend to be from the early post-war years – the imposition of a settlement in British Mandate Palestine, leading to the declaration of the State of Israel, and the partition of India. But with the post-1989 changes in Central and Eastern Europe, states either kept their earlier borders, broke along lines of federal division, or fought wars where these issues were significant.

Some of the enduring territorial issues follow from this broad principle – the republics of the Soviet Union became states, with the borders they had at the time, but regions within a Soviet republic did not. Georgia, Azerbaijan and Armenia became states, Chechnya and Dagestan did not. This led in some instances to populations being outside the state with which they perhaps felt most affinity. Areas with strong external support, such as Transnistria in Moldova, could survive as de facto states, even without recognition.

Especially in the post-Cold War era, the right of states to exercise sovereignty without restriction came under scrutiny, especially in the idea of humanitarian intervention or later the responsibility to protect. This was later expanded in the ‘war on terror’ into an idea that was sometimes known as ‘contingent sovereignty’. On this argument, made especially by neo-conservatives of the George W. Bush administration, sovereignty was not absolute, at least for some states, but was conditional. If a state violated certain norms – its treatment of civilian populations, pursuit of weapons of mass destruction or harbouring terrorists – then other states could, the claim went, intervene within its borders. When I discussed this, especially in Terror and Territory, I suggested that one part of the idea of territorial integrity – the exclusive power of a state within its borders – was being increasingly challenged. Yet at the same time, often quite a lot of effort was made to prevent a state’s territory from fracturing along ethnic or other lines. Somalia is still the recognised state, though there is no government which exercises authority over all of its territory, and there are areas within it such as Somaliland which are more viable, yet not recognised, states. Once Saddam Hussein had been overthrown, a key part of the enduring occupation of Iraq was to prevent territorial fragmentation from happening. Kosovo was an example of where an intervention to prevent Serbia from acting towards its population in a part of a territory created a problem the existing system was ill-prepared to resolve. Eventually Kosovo became a recognised state by just over half of United Nations states. But I argued that breaking one part of the post-World War Two settlement risked its entire basis.

A territorial free-for-all would inevitably create the kind of instability in the international system that existing frameworks are designed precisely to avoid. But pulling at one thread in the international framework risks unravelling the whole (Terror and Territory, p. 174).

It feels like some of this is behind what is happening at the moment. Russia’s invasion of Ukraine was widely condemned, but its 2008 invasion of Georgia, and establishment of unrecognised states in Abkhazia and South Ossetia, did not receive nearly as much attention. Nor did the seizure of Crimea from Ukraine in 2014, and the promotion of secessionist groups in the Donbas. I briefly wrote about Georgia in Terror and Territory, and said a little on this site in 2014 about the invasion of Crimea and territorial integrity. Gerard Toal has explored these issues in much more detail in his 2017 book Near Abroad: Putin, the West, and the Contest over Ukraine and the Caucasus, and more recently in the 2024 article “The Territorial Taboo”.

When the new US administration came to power at the beginning of 2025, claims made about Greenland or Panama were widely ridiculed. But I wondered at the time if they were part of a wider challenge to the idea of territorial integrity. If a settlement is imposed on Ukraine which requires it to cede some of its territory, then the borders of a state will have been redrawn by force.* The Syrian civil war and the collapse of the Assad regime in Syria led neighbouring states to claim territory there, often described as some kind of buffer zone, even if what is notionally being protected is already illegally seized territory. Israel seems ever more determined to make unilateral declarations of annexation, some explicitly designed to make a viable Palestinian state impossible – despite or potentially because of the belated recognition of such a state by many world powers in recent months. China’s attitude to Taiwan, which it describes as a breakaway province, is another example; in contrast, the government in Taipei claims to be the legitimate government of the whole of China.

The post-World War Two settlement was far from ideal, of course, and the list of grievances and failures of the United Nations is long. But the aspirations behind it remain ones which are worth defending, and the territorial integrity principle was better than alternatives. This does not mean that there were not invasions of countries, seizure of territory and enduring boundary disputes after 1945. But claims to territory were generally not recognised by the international community, or at least not unanimously – consider the cases of Northern Cyprus, Western Sahara, Israel’s occupation of the West Bank and Gaza, the Golan, and other cases. What the Locarno Treaties were designed to prevent was another war on the European continent. Their aspiration was carried forward on a global scale into the United Nations Charter. Equally, territorial disputes between two members of the European Union are limited – until the United Kingdom left the EU, the status of Gibraltar was a rare exception.

Territorial disputes continue today, of course, but Locarno was trying to prevent them, or at least to find a framework through which they could be resolved. We might return to the ideal behind Locarno, and the relation between territorial preservation and territorial sovereignty as territorial integrity, as we navigate our own troubled times.

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* Quite apart from its political problems, one peculiarity of the 28-point US-Russia plan for Ukraine was point 21: “Crimea, Luhansk and Donetsk will be recognised as de facto Russian, including by the United States”. One of the usual ways of determining legal status is recognition, so the idea that something might be recognised as de facto, rather than redrawn de jure is in tension. But either way, it would be a limitation of Ukraine’s territorial integrity. If it loses some of its territory, then its territorial integrity has clearly been breached, with borders redrawn by force. If parts of its legal territory continue to be controlled by Russia, then Ukraine will be unable to exercise sovereignty within its entire territory, again a limitation of its territorial integrity.

Update: I should have also indicated Reece Jones’s recent critical discussion, “Political Geography II: The End of Territorial Integrity”, Progress in Human Geography, 2025, online first

References and Further Reading

The Avalon Project, https://avalon.law.yale.edu/default.asp (extensive collection of treaties and other documents in international law)

Seyla Benhabib and Ayelet Shachar eds. Lawless Zones, Rightless Subjects: Migration, Asylum, and Shifting Borders, Cambridge: Cambridge University Press, 2025.

Franck Billé, Somatic States: On Cartography, Geobodies, Bodily Integrity, Durham, NC: Duke University Press, 2025.

Jordan Branch, The Cartographic State: Maps, Territory and the Origins of Sovereignty, Cambridge: Cambridge University Press, 2014.

Nina Caspersen, Unrecognized States: The Struggle for Sovereignty in the Modern International System, Cambridge: Polity, 2013.

Klaus Dodds, Border Wars: The Conflicts that will Define our Future, London: Ebury, 2022.

Stuart Elden, “Territorial integrity and the war on terror“, Environment and Planning A 37, 2005, 2083-2104.

Stuart Elden, “Blair, Neo-Conservatism and The War on Territorial Integrity“, International Politics 44, 2007, 37-57.

Stuart Elden, Terror and Territory: The Spatial Extent of Sovereignty, Minneapolis: University of Minnesota Press, 2009.

Stuart Elden, The Birth of Territory, Chicago: University of Chicago Press, 2013.

Abdelhamid El Ouali, Territorial Integrity in a Globalizing World: International Law and States’ Quest for Survival, Berlin: Springer, 2012.

Kerry Goettlich, “Territorial Integrity as an Etiquette of Thieves: Non-conquest in Nineteenth-Century Imperialism”, International Organization 2025, doi:10.1017/S0020818325101124

Jean Gottmann, The Significance of Territory, Charlottesville: University Press of Virginia, 1973.

Reece Jones, “Political Geography II: The End of Territorial Integrity“, Progress in Human Geography, 2025, online first

Suzanne Lalonde, Determining Boundaries in a Conflicted World: The Role of Uti Possidetis, Montreal: McGill-Queen’s University Press, 2002.

Matthew Longo, The Politics of Borders: Sovereignty, Security, and the Citizen After 9/11, Cambridge: Cambridge University Press, 2017.

Margaret Moore, A Political Theory of Territory, Oxford University Press, 2015.

Paulina Ochoa Espejo, On Borders: Territories, Legitimacy, and the Rights of Place, Oxford: Oxford University Press, 2020.

Jamie Scudder, “Territorial Integrity – Modern States and the International System”, Exploring Geopolitics, 2010, https://exploringgeopolitics.org/publication_scudder_jamie_territorial_integrity_modern_states_international_political_system_jurisdiction_peace_westphalia_lebanon_somalia/

David Storey, Territories: The Claiming of Space, London: Routledge, third edition, 2024.

Gerard Toal, Near Abroad: Putin, the West and the Contest over Ukraine and the Caucasus, Oxford: Oxford University Press, 2017.

Gerard Toal, “The Territorial Taboo: Explaining the Public Aversion to Negotiations in the Ukraine War Support Coalition”, Environment and Planning C: Politics and Space 42 (7), 1108-27.

Jonathan Wright, “Locarno: A Democratic Peace?”, Review of International Studies 36 (2), 2010, 391-411.

Mark W. Zacher, “The Territorial Integrity Norm: International Boundaries and the Use of Force”, International Organization 55, 2001, 215-30.

Maja Zehfuss and Nick Vaughan-Williams, “From Security-Space to Time-Race: Reimagining Borders and Migration in Global Politics”, International Political Sociology 18 (3), 2024, https://doi.org/10.1093/ips/olae019

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This is the 48th post of a weekly series, where I post short essays with some indications of further reading and sources, but which are not as formal as something I’d try to publish more conventionally. They are usually tangential to my main writing focus, a home for spare ideas, asides, dead-ends and possible futures. I hope there is some interest in them. They are provisional and suggestions are welcome. A few, usually shorter, pieces in a similar style have been posted mid-week.

The full chronological list of ‘Sunday histories’ is here, with a thematic ordering here.