Polish nationalist candidate Karol Nawrocki has narrowly won the country’s presidential runoff, securing 50.89% of the vote, according to official results released by the electoral commission early Monday. His victory deals a setback to the pro-European government led by Prime Minister Donald Tusk.

Nawrocki’s opponent, Rafal Trzaskowski — the liberal mayor of Warsaw and a close ally of Tusk — received 49.11% of the vote. Initial exit polls on Sunday had projected a narrow win for Trzaskowski, making the final result a surprise for many observers.

At 42, Nawrocki is a historian and former head of Poland’s national remembrance institute. Running as a eurosceptic with backing from the conservative Law and Justice (PiS) party, he campaigned on a nationalist platform, vowing to prioritize the needs of Polish citizens over foreigners, including Ukrainian refugees.

His past came under scrutiny in the final days of the campaign, including questions about his acquisition of an apartment from a pensioner and an admission of involvement in organized fights during his youth. Nevertheless, he managed to rally nationalist voters and secure the presidency.

Though the Polish parliament holds the bulk of political power, the presidency holds significant influence through the power to veto legislation. As such, the result is expected to impact the Tusk government’s ability to implement key reforms, including efforts to liberalize abortion laws and overhaul the judiciary.

Nawrocki is expected to follow in the footsteps of outgoing President Andrzej Duda, a fellow PiS ally, particularly in opposing the government’s progressive reform agenda.

The closely watched election drew international attention, especially from Ukraine, Russia, the European Union, and the United States, given its implications for regional policy and EU relations.

Voter turnout reached a record 71.31% for a second-round presidential vote, the electoral commission reported.

Outgoing President Duda posted on social media platform X, expressing gratitude to voters:

“Thank you! For participating in the presidential elections. For the turnout. For fulfilling your civic duty. For taking responsibility for Poland. Congratulations to the winner! Stay strong Poland!”