Polish Prime Minister Donald Tusk and French President Emmanuel Macron signed the Treaty on Enhanced Cooperation and Friendship between the Republic of Poland and the French Republic. The document was signed in a symbolic location – Nancy, the city where Stanisław Leszczyński, King of Poland in the 18th century, once lived. The new Polish-French treaty replaces the 1991 agreement. It is the first such treaty France has signed with a country it does not share a border with. The treaty provides for annual joint government meetings and opens the way for work on further agreements. It covers areas such as the economy and nuclear energy, but according to the Polish Prime Minister, “the absolutely most important issue was mutual security guarantees.” The treaty includes provisions for mutual military assistance and bilateral security guarantees. Nuclear umbrella? The treaty in itself guarantees nothing, but it opens the door for further agreements, including in the field of defense technologies and the nuclear umbrella. It should be seen primarily as an expression of political will rather than a concrete commitment. The path to recognizing Poland as a vital interest of France – which is required under France’s nuclear doctrine – is still long. Speculation about being included under a nuclear umbrella has been ongoing in Poland for some time. The public debate has touched on participation in the US Nuclear Sharing program, but that now seems unlikely. Currently, Poland has one nuclear reactor, which is used for research and medical purposes. The reactor is shut down; it was supposed to resume operation on Friday, May 9, but due to problems with extending the operating license, the process has been delayed. In 1999, the transition from highly enriched uranium to low-enriched fuel began. This transition was in response to international initiatives aimed at limiting the spread of high-risk nuclear materials. Given the current threat from Russia, Poland would likely think twice before making such a decision – just as Ukraine might have before signing the Budapest Memorandum. During a press conference, the Polish Prime Minister noted that Poland and France had also signed treaties in 1939, just before the outbreak of World War II. After Germany’s invasion of Poland, France and the United Kingdom did declare war on Hitler, but only at a declarative level. No military aid was provided to Poland, which was left to defend itself, and the war engulfed Europe and the world for six years. The signing of the treaty is significant but largely symbolic. It opens the path to closer cooperation, but that requires effort and sustained political will from both countries – something that cannot be taken for granted in times of political instability and in the long-term perspective. Nevertheless, both this event and the visit by German Chancellor Friedrich Merz the day before – respectively to France and Poland – signal a desire to restart the functioning of the Weimar Triangle of France, Germany and Poland. The consolidation of efforts by European countries is also a result of the unpredictable policies of the United States.