Karol Nawrocki, Poland's president, right, and Volodymyr Zelenskiy, Ukraine's president, arrive at a news conference at the Presidential Palace in Warsaw, Poland, on Friday, Dec. 19, 2025.(Damian Lemanski/Bloomberg via Getty Images)History is rattling Ukraine-Poland relations, yet again.The new round of historic grievances erupted in Poland when President Volodymyr Zelensky named a Ukrainian special forces unit after the Ukrainian Insurgent Army (UPA) — an organization that fought for Ukrainian independence during and after World War II, but which evokes painful memories in Poland.In Ukraine, the UPA represents a historical struggle against Moscow's domination — a legacy that feels especially alive amid Russia's full-scale invasion.But in Poland, UPA fighters are seen chiefly as perpetrators of mass killings of Poles in the region of present-day western Ukraine, then under Nazi occupation.Zelensky's move was denounced by Polish public figures across parties and ideologies, despite Kyiv's assurances that it was not meant to offend its western neighbors.What happened?When Ukraine adopted a decree on May 26 naming a unit "in honor of the Heroes of the UPA" — supposedly at the soldiers' request — the reaction from Poland was swift.Polish officials and public figures denounced the step as insensitive and hurtful, especially in light of the Polish support provided to Ukraine since the outbreak of the full-scale invasion.Karol Nawrocki, a Polish historian-turned-president, proposed stripping Zelensky of Poland's highest state honor, the Order of the White Eagle, which was conferred on him in 2023 by then-Polish President Andrzej Duda.President Volodymyr Zelensky and Polish President Andrzej Duda attend a commemoration for the victims of the Volyn Massacre in Lutsk, Ukraine, on July 9, 2023. (Maxym Marusenko / NurPhoto / Getty Images)Przemyslaw Czarnek, the conservative Law and Justice (PiS) party's candidate for prime minister in the upcoming elections, denounced Kyiv's move as a "slap in the face," while the far-right Confederation party called for barring Ukraine's path to the EU.Even Ukraine-friendly figures expressed their disappointment.Lech Walesa, a former anti-communist dissident and later president who has been a vocal supporter of Kyiv, removed his Ukrainian flag pin in personal protest against Zelensky.Poland's Prime Minister Donald Tusk, otherwise a political rival of the Polish president, expressed a rare understanding of Nawrocki's response — even as he warned against allowing Moscow to drive a wedge between Kyiv and Warsaw.