The Polish-Ukrainian controversy is becoming more and more toxic, spilling into unexpected places.

The relationship between Poland and Ukraine, once considered one of Europe's most critical strategic alliances, has reached a historic low following a decision made by Ukrainian President Volodymyr Zelenskyy. This development marks a significant shift in the dynamics between the two nations, which have been deeply intertwined since the Russian invasion of Ukraine in February 2022. Since then, Poland has played a pivotal role as a logistical hub for Western military aid, with the Jasienka Airport in Rzeszów serving as a crucial transit point for weapons, ammunition, and humanitarian supplies destined for Ukraine. However, this vital connection appears to be under strain due to recent political decisions on both sides.

Zelenskyy’s recent diplomatic moves have raised eyebrows among Polish officials and analysts alike. Instead of traveling through Poland, he opted to fly directly from Kyiv to London for meetings with UK Prime Minister Keir Starmer, French President Emmanuel Macron, and German Chancellor Olaf Scholz. He later traveled to the G7 summit in France from Chisinau, Moldova, bypassing Poland entirely. This choice was not arbitrary; it reflects a growing rift between the two countries, exacerbated by Zelenskyy’s decision to rename a special forces unit after the "Heroes of the UPA" — the Ukrainian Insurgent Army.

This move reignited tensions over historical grievances tied to the UPA, a nationalist group active during World War II. The UPA fought against both Soviet and Nazi forces but also clashed with Polish units, particularly in areas that were part of pre-war Poland, such as Volhynia. The conflict culminated in mass killings of Poles in 1943, an event known in Poland as the "Bloody Sunday." These atrocities remain a sensitive topic in Polish history, with estimates suggesting up to 100,000 Polish civilians were killed, though Ukrainian authorities officially acknowledge fewer casualties and emphasize the reciprocal nature of violence during the war.

Poland’s reaction to Zelenskyy’s naming of the unit was swift and severe. President Andrzej Duda withdrew the highest Polish state honor, the Order of the White Eagle, from Zelenskyy, while Ukrainian officials responded in kind. Kirill Budanov, head of the presidential administration, and Vasyl Bodnar, the Ukrainian ambassador in Warsaw, resigned from their positions on the Order of Merit of the Republic of Poland. Former President Leonid Kuchma also returned a medal awarded to him nearly three decades ago. These symbolic gestures underscore the deepening diplomatic crisis between the two nations.

The dispute has roots in broader historical sensitivities. While Ukraine has acknowledged the UPA’s involvement in attacks on Poles and formally apologized for these actions, it continues to view the organization as a symbol of resistance against foreign occupation. In contrast, Poland sees the UPA and its leader Stepan Bandera as symbols of genocide, a perspective reinforced by the official recognition of July 11 as a day of remembrance for victims of the Volhynian massacres.

Despite past tensions, including instances where Polish right-wing politicians stirred anti-Ukrainian sentiment, the current level of hostility is unprecedented since the start of Russia’s full-scale invasion. The situation has been further complicated by internal politics in both countries. In Poland, the ruling party PiS has historically taken a hardline stance on historical issues, while opposition parties like the Civic Platform advocate for reconciliation. Meanwhile, in Ukraine, the renaming of the unit was seen as a necessary step to honor historical figures who fought for independence, even if they are controversial in Poland.

The implications of this rift extend beyond bilateral relations. As a major NATO member and a key supplier of military equipment to Ukraine, Poland’s support has been instrumental in sustaining Ukraine’s defense efforts. However, the current diplomatic cooling could affect the flow of resources and cooperation. Some analysts suggest that the issue might be resolved through high-level dialogue, although neither side seems willing to back down easily.

Looking ahead, the situation remains uncertain. Both countries face domestic pressures and external challenges that could either exacerbate or ease the tension. For now, the legacy of wartime conflicts continues to cast a long shadow over contemporary diplomacy, testing the resilience of a partnership once deemed unbreakable.