Before even taking office, US President-elect Donald Trump caused alarm by discussing the annexation of Canada, Greenland and Panama. While these remarks were largely dismissed as unserious and met with mockery, the notion that the soon-to-be leader of the free world might support redrawing international borders – and moreover by force – could have serious repercussions. 

These statements may resonate particularly strongly in the Balkans, where border disputes remain a volatile issue. The region’s history of ethnic conflict and territorial claims makes it acutely sensitive to any suggestion of redrawing boundaries.

Already, Bulgarian far-right politician Kostadin Kostadinov has seized on Trump’s comments to advocate for annexing parts of Ukraine and the whole of North Macedonia, demonstrating the dangerous ripple effects of such rhetoric.

German Chancellor Olaf Scholz was among the global leaders to respond negatively to Trump’s comment, saying that "the inviolability of borders is a universal principle." Without naming Trump directly, Scholz’s remarks highlighted the unease felt in Europe. 

“Borders must not be moved by force,” he said, drawing a parallel to Russia’s violation of this principle in Ukraine. 

“The principle of the inviolability of borders applies to every country, regardless of whether it lies to the east of us or the west, and every state must keep to it, regardless of whether it is a small country or a very powerful state,” he added. 

Serbia-Kosovo land swap

After former Yugoslavia was torn apart by bloody ethnic wars in the 1990s, the spectre of border changes is not new to the Balkans.

Since then the issue has continued to be raised sporadically. Milorad Dodik, president of Bosnia & Herzegovina’s Republika Srpska, in particular, has repeatedly talked of the secession of Bosnia’s Serb entity and its potential unification with Serbia post-independence. 

A controversial proposal for a land swap between Serbia and Kosovo has also been mooted as a potential way to resolve the ongoing tensions in Serb-majority areas in northern Kosovo.

This resurfaced in 2018, sparking widespread criticism. The plan, supported by Serbian President Aleksandar Vucic and Kosovo’s then president Hashim Thaci, suggested exchanging ethnic Albanian-majority territories in southern Serbia for parts of northern Kosovo. Advocates claimed this could resolve long-standing tensions, paving the way for Kosovo to gain a UN seat and advancing EU accession talks for both countries.

Despite US support under Trump’s then national security adviser John Bolton, the plan faced fierce resistance in Kosovo and elsewhere in the Balkans.

Critics warned that such a move could destabilise the region. Kosovo’s then prime minister Ramush Haradinaj condemned the proposal as a “disastrous idea”, arguing it could reignite ethnic conflicts. Then German Chancellor Angela Merkel strongly opposed the plan, while former international representatives to Bosnia warned it could plunge the region back into division. Three former high representatives for Bosnia – Carl Bildt, Paddy Ashdown and Christian Schwarz-Schilling – wrote an open letter saying they could “think of no policy more likely to lead us back to division and conflict in the Balkans”.

The mystery of the ‘non-papers’

Three years later, in 2021, a diplomatic firestorm erupted over leaked “non-papers” – unofficial documents proposing redrawn borders in the Balkans. These proposals included the “peaceful dissolution” of Bosnia, with Serbia and Croatia annexing large portions, as well as the unification of Kosovo and Albania. 

Valentin Inzko, the then high representative in Bosnia, warned that such ideas could open “Pandora’s box”, jeopardising the region’s fragile peace. “Frozen conflicts can break out at any time,” he warned, citing recent flare-ups in fighting in Nagorno-Karabakh and Palestine.

The non-papers drew widespread condemnation, though Bosnia’s Dodik voiced support for their secessionist implications. Accusations then flew about the origins of the papers, with some even speculating about Franco-German involvement. Slovenia’s then prime minister, Janez Jansa, was among those under scrutiny, while Kosovo’s President Vjosa Osmani accused Serbia of orchestrating the documents, which Belgrade denied.

Wider instability

The ramifications of reopening border disputes extend beyond Serbia and Kosovo. North Macedonia – the target of Kostadinov’s proposal – has expressed concerns about land swaps potentially reigniting ethnic tensions. Back in 2018, Radmila Sekerinska, the country’s then defence minister, told The Guardian that such ideas harken back to the Balkan wars of the 1990s, when ethnic divisions led to atrocities. “Political solutions to political problems do not require ethnic borders,” she said. 

Specifically, the fear is that that reopening one territorial dispute could embolden nationalist movements across the Balkans, destabilising fragile peace agreements. Ethnic Serbs in Bosnia’s Republika Srpska, for example, could intensify calls for secession, while Serbs and Macedonians fear Albanian nationalists might make their own demands. 

The “Serbian World” and “Greater Albania”

Serbia’s Deputy Prime Minister Aleksandar Vulin has promoted the concept of a “Serbian World” (“Srpski svet”), advocating the unification of all ethnic Serbs across the Western Balkans. This vision echoes the “Greater Serbia” agenda that fuelled Slobodan Milosevic’s military campaigns in the 1990s, marked by territorial expansion and widespread atrocities. 

Historian and political analysts Jasmin Mujanovic has described it as “perhaps the most dangerous idea in European politics today, and therefore a threat to the entire continental order”. 

The concept of a “Greater Albania” (“Shqipëria e Madhe”) envisions uniting territories with historical or current Albanian populations, including Kosovo, parts of Serbia’s Preševo Valley, Montenegro, North Macedonia and northwestern Greece, has also periodically surfaced. 

While “Greater Albania” is not promoted by Albanian politicians, symbols associated with the concept continue to spark tensions. Albania’s football association was charged at the Euro 2024 championship after fans displayed a map of “Greater Albania” as well as “transmitting a provocative message unfit for a sports event”. In 2020 Kosovo-born British pop star Dua Lipa shared a “Greater Albania” map on Twitter, but quickly back-pedalled, saying her post was “never meant to incite any hate”.  

Fears of renewed instability 

Already, the prospect of Trump’s return to the White House raises fears of renewed instability in the Balkans. During his first term, Trump’s administration adopted an unorthodox approach to the region, including backing the Serbia-Kosovo land swap concept. Critics worry that a second Trump presidency could embolden nationalist actors like Serbia’s Vucic or Bosnia’s Dodik. 

A recent report by the European Council on Foreign Relations (ECFR) warns that Trump’s foreign policy could shift from a neutral stance to openly favouring Serbian interests. This, the report argues, could undermine efforts to maintain the delicate balance of power in the Western Balkans, reignite calls for contentious border changes, and embolden secessionist movements.

The resurgence of nationalist rhetoric and territorial ambitions in the Balkans poses a serious challenge to regional stability. Politicians like Dodik and Vulin capitalise on such narratives to strengthen their domestic positions, while external actors like Russia and Turkey exploit these divisions to expand their influence. 

Trump’s unpredictable foreign policy and apparent indifference to established international norms could further embolden these forces, complicating efforts to maintain peace. The US president elect’s casual rhetoric about annexations – even when unserious – risks legitimising dangerous ideas about border changes. As the European Union struggles to maintain unity and the US’ commitment to international norms appears uncertain, the potential for renewed instability in the Balkans looms large.