Warsaw’s liberal mayor and his insurgent populist challenger are locked in a dead heat as they fight for the presidency of Poland, exit polls projected after Sunday’s head-to-head vote, leaving the country tilting between two wildly different political futures.

Exit polls showed Rafał Trzaskowski and Karol Nawrocki essentially tied, with Trzaskowski ahead by less than one percentage point after Sunday’s run-off election.

Should Trzaskowski prevail, he would end the Law and Justice (PiS) party’s 10-year occupancy of the presidential palace – the last political stronghold of the populist bloc that once ruled Poland with near-total authority – and see the mayor claim nationwide power at the second attempt.

But the margins were close enough to throw both candidates – and the country’s 38 million residents – into a nervous night of counting, with a final result likely to be announced in the coming hours.

The result carries huge significance for Prime Minister Donald Tusk, whose pledge to erase PiS’ fingerprints from Poland’s embattled institutions saw him clash repeatedly with Andrzej Duda, the outgoing president who defeated Trzaskowski in 2020. Nawrocki, like Duda before him, was backed by PiS.

A Nawrocki presidency could torpedo the centrist government’s efforts to unspool the legacy of authoritarianism in the country; the 42-year-old historian would be able to yield the hugely powerful presidential veto, which Duda used frequently to thwart Tusk’s agenda.

Trzaskowski, by contrast, would be expected to essentially give Tusk an open road to press ahead with his ambitious aim of undoing the effects of PiS’ transformation of Poland, an effort that has been bogged down in recent months.

The PiS candidate is a vocal supporter of US President Donald Trump, whom he visited in the campaign’s final weeks, and received a late flurry of support from attendees at the Conservative Political Action Conference (CPAC), which held its first-ever gathering in Poland earlier this week, cementing a years-long convergence between the populist right movements in Poland and the US.

Trzaskowski, the worldly son of a celebrated Polish jazz musician, was viewed as the favorite in the election campaign, until the first round of voting two weeks ago showed him only narrowly ahead of Nawrocki and revealed greater levels of support than expected for a smattering of far-right and extreme-right figures, some of whom subsequently said they would vote for Nawrocki.

Nawrocki is a first-time politician who has led two influential cultural bodies in Poland – the Museum of the Second World War in Gdansk, and then the Institute of National Remembrance, a state-funded research facility whose purpose became increasingly politicized as PiS took a nationalistic approach to the telling of Polish history. On the campaign trail, he emphasized his Catholic faith, pledged to reduce migration, and was relentlessly critical of Brussels and of Tusk.

This is a developing story and will be updated.