Poland and Germany renew historic ties to defend Europe's eastern flank
Relations between Poland and Germany have been marked by a long and complicated history.
During World War II, Nazi Germany occupied much of Poland and killed nearly 6 million Polish citizens. After the war, much of Poland's territory was annexed by the Soviet Union.
One of the key sticking points to renewing ties was the recognition of the post-war border between Germany and Poland, the Oder-Neisse Line. While communist governments in Poland and East Germany agreed to move the border westward, West Germany resisted.
While there was a normalisation in relations between the countries in the 1970s, known as "Ostpolitik", the real turning point came with the collapse of communism and restoration of democracy in Poland in 1989 and the reunification of Germany the following year.
The Treaty on Good Neighbourliness, Friendship and Cooperation, signed on 17 June 1991, opened a new chapter in relations between the two countries. It came just months after the confirmation of the Oder-Neisse line came on 14 November 1990.
Its 38 articles established a wide-ranging cooperation from economic and scientific partnerships, infrastructure, security and arms control.
It also saw Germany bring its full support to Poland for accession to the European Union in 2004 and NATO in 1999.
Behind the politics, there was a focus on encouraging cultural exchanges, with the creation of the German-Polish Youth Office, as well as a clause to protect the rights of national minorities and their languages on both sides.
Past not forgotten
Russia's full-scale war on Ukraine in 2022 brought the two countries even closer. Both Poland and Germany have taken in large numbers of Ukrainian refugees and supported Ukraine with direct financial aid and military assistance.
It is in this spirit of historic cooperation that the two countries chose to deepen their mutual support, with the signing of a new defence agreement on the anniversary of the Good Neighbourliness Treaty.
"We are not forgetting the past," Polish defence minister Wladyslaw Kosiniak-Kamysz said in Warsaw on Wednesday, at a press conference alongside his German counterpart Boris Pistorius. "But the politics of the future, development and security are our obligation."
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Posting on social media platform X, Kosiniak-Kamysz wrote: "Poland and Germany are united by the belief that Europe's security begins on its eastern flank. That's why today we signed an agreement so that in the event of a crisis, NATO forces can reach the eastern flank more quickly, the Baltic Sea can be better protected, and the East Shield becomes stronger."
Poland is keen to ensure that major European allies take a greater role in defending the continent's eastern flank, as the United States reviews its military presence in Europe.
Polish media reports claimed there were plans for a more ambitious pact, but that Prime Minister Donald Tusk's government opted for a reduced version, expecting opposition from nationalist President Karol Nawrocki and the far-right Law and Justice (PiS) party.
'Equal partner'
Poland's importance as a logistics hub for Ukraine, alongside its growing economy and heavy defence investment, has made it a compelling partner for Germany.
"Poland started building a strong army much earlier than other countries in Western Europe," Polish deputy defence minister Cezary Tomczyk told reporters. "So we are ahead when it comes to capabilities."
The Polish government also wants Warsaw to be included in decisions about the region's future. "We definitely don't accept that any agreements about this part of Europe are made without Poland," Tomczyk said.
Meanwhile, Germany is revitalising its military, the Bundeswehr, after decades of neglect. It has ambitions to build the strongest conventional army on NATO's European side, an effort that will make it a central pillar of European defence in the years ahead.
In December, German Chancellor Friedrich Merz said after meeting Tusk in Berlin: "We Germans need a strong Poland as an equal partner. This is in our fundamental interest."
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Baltic region
The defence agreement is expected to include plans for protecting the Baltic Sea region, as well as cooperation on military mobility and infrastructure, cyber defence and new technology.
The two countries are irreversibly tied to NATO's defence plans, which give Germany a key role in defending the Baltic region, together with Poland and other countries in central and eastern Europe, said Justyna Gotkowska, deputy director of Warsaw-based think tank the Centre for Eastern Studies.
"Germany is largely responsible for the defence of the Baltic states and without cooperation with Poland, that will not happen," she said.
The Baltic countries are often described as the most likely target for Russia if it were to attack NATO territory in the future.
German soldiers, among others, would help further develop Poland's East Shield, a system of enhanced fortifications the country has been building on its borders with Belarus and Russia since 2024, Tomczyk said.
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Political limits
The agreement is also expected to reaffirm the mutual defence obligations set out in NATO and European Union treaties, while focusing mainly on practical military cooperation.
However, it stops short of the wider political defence pledges Poland and Germany have each signed with France and the United Kingdom.
This more limited format reflects the political sensitivity of Polish-German relations. The PiS has previously demanded reparations from Germany over its occupation of Poland in World War II – a demand Berlin rejected.