France and Poland Sign Mutual Defense Pact Amid Push for European Security Independence

The new treaty strengthens military and nuclear energy cooperation amid doubts over the future of U.S. support.

French President Emmanuel Macron and Polish Prime Minister Donald Tusk sign the French-Polish Friendship and Strategy Pact in Nancy, France, on May 9, 2025. Christophe Petit Tesson/Reuters

France and Poland have signed a bilateral treaty to strengthen cooperation in defense, nuclear energy, and technological innovation—an agreement that reflects Europe’s broader efforts to assume more responsibility for its own security as the United States shifts its focus to the Asia-Pacific region to counter China’s threat.

The pact—signed on May 9 by Polish Prime Minister Donald Tusk and French President Emmanuel Macron during a ceremony in Nancy, France—includes a mutual assistance clause affirming that the two NATO allies will support one another in the event of an attack. It also outlines commitments to deepen military collaboration and expand partnerships in strategic sectors, including civil nuclear energy.

“I am deeply convinced that from today France and Poland in these difficult times will be able to count on each other in every situation,” Tusk said at the signing.

While the agreement does not reference nuclear weapons or deterrence explicitly, it comes amid ongoing European discussions about strengthening the continent’s security architecture. In March, Macron expressed openness to extending France’s nuclear deterrent to other European allies. At the time, he cited growing uncertainty about long-term transatlantic defense guarantees and emphasized the importance of opening a strategic dialogue within Europe.

“Our nuclear deterrent protects us: It’s complete, sovereign, French through and through,” Macron said in a national address. “But, responding to the historic call of the future German chancellor, I have decided to open the strategic debate on the protection of our allies on the European continent through our [nuclear] deterrence.”

Macron’s call came after Germany’s incoming chancellor, Friedrich Merz, raised questions about NATO’s future structure and advocated broader European discussions on nuclear defense—particularly in the face of ongoing threats from Russia.

Though the Polish–French treaty stops short of addressing a nuclear umbrella, it does lay the groundwork for deeper integration in civil nuclear technologies, with France aiming to share its expertise as part of a broader energy partnership.

The agreement also underscores Poland’s growing strategic role in Europe. With defense spending reaching 4.12 percent of GDP—the highest among NATO members—and its position along NATO’s eastern flank, Poland has emerged as a key security player in the region.

Tusk has emphasized the importance of complementing Warsaw’s longstanding security ties with the United States by building stronger partnerships within Europe. At the same time, Polish President Andrzej Duda has called on Washington to consider moving U.S. nuclear weapons eastward, suggesting Poland as a potential host. In a March interview with Financial Times, Duda argued that NATO’s military infrastructure should reflect the alliance’s eastward expansion over the past two decades.

“The borders of NATO moved east in 1999, so 26 years later there should also be a shift of the NATO infrastructure east,” Duda said. “For me this is obvious. I think it’s not only that the time has come, but that it would be safer if those weapons were already here.”

Duda’s comments followed Russia’s June 2023 deployment of nuclear weapons to Belarus—16 months after Russia’s invasion of Ukraine. At the time, Russian President Vladimir Putin described the move as a deterrent against any state seeking to inflict a “strategic defeat” on Moscow.

Tusk, meanwhile, has made clear that Poland’s enhanced cooperation with France is not a substitute for its alliance with the United States, but part of a broader strategy to strengthen security through both transatlantic and intra-European partnerships.

He also said Poland and France would work together to support Ukraine and promote peace, though no further details were provided.

The Polish–French treaty was signed one day before Ukraine was due to host leaders of a “coalition of the willing”—a group of countries led by France and Britain aiming to increase military and political support for Kyiv as the conflict continues and as questions linger over future U.S. engagement.

Days earlier, Macron and Merz announced a new Franco-German security council during the German leader’s first trip abroad after assuming office, with the move signaling Europe’s continued push to reshape its defense posture.