Voters in Turkey return to the polls Sunday to decide whether the country’s longtime leader stretches his increasingly authoritarian rule into a third decade or is unseated by a challenger who has promised to restore a more democratic society.

President Recep Tayyip Erdogan, who has been at Turkey’s helm for 20 years, is favored to win a new five-year term in the second-round runoff after coming just short of an outright victory in the first round on May 14.

The divisive populist who turned his country into a geopolitical player finished four percentage points ahead of Kemal Kilicdaroglu, the candidate of a six-party alliance and leader of Turkey’s center-left main opposition party. Erdogan’s performance came despite crippling inflation and the effects of a devastating earthquake three months ago.

Kilicdaroglu (pronounced KEH-lich-DAHR-OH-loo), a 74-year-old former bureaucrat, has described the runoff as a referendum on the country’s future.

More than 64 million people are eligible to cast ballots when the polls open at 8 a.m.

Turkey does not have exit polls, but the preliminary results are expected to come within hours of the polls closing at 5 p.m.

The final decision could have implications far beyond Ankara because Turkey stands at the crossroads of Europe and Asia, and it plays a key role in NATO.

Turkey vetoed Sweden’s bid to join the alliance and purchased Russian missile-defense systems, which prompted the United States to oust Turkey from a U.S.-led fighter-jet project. But Erdogan’s government also helped broker a crucial deal that allowed Ukrainian grain shipments and averted a global food crisis.

The May 14 election saw 87% turnout, and strong participation is expected again Sunday, reflecting voters’ devotion to elections in a country where freedom of expression and assembly have been suppressed.

If he wins, Erdogan, 69, could remain in power until 2028. After three stints as prime minister and two as president, the devout Muslim who heads the conservative and religious Justice and Development Party, or AKP, is already Turkey’s longest-serving leader.

The first half of Erdogan’s tenure included reforms that allowed the country to begin talks to join the European Union and economic growth that lifted many out of poverty. But he later moved to suppress freedoms and the media and concentrated more power in his hands, especially after a failed coup attempt that Turkey says was orchestrated by the U.S.-based Islamic cleric Fethullah Gulen. The cleric denies involvement.

Erdogan transformed the presidency from a largely ceremonial role to a powerful office through a narrowly won 2017 referendum that scrapped Turkey’s parliamentary system of governance. He was the first directly elected president in 2014 and won the 2018 election that ushered in the executive presidency.

The May 14 election was the first that Erdogan did not win outright.

Critics blame Erdogan’s unconventional economic policies for skyrocketing inflation that has fueled a cost-of-living crisis. Many also faulted his government for the slow response to the earthquake that killed more than 50,000 people in Turkey.

Still, Erdogan has retained the backing of conservative voters who remain devoted to him for lifting Islam’s profile in the country that was founded on secular principles and for raising the country’s influence in world politics.

In a bid to woo voters hit hard by inflation, he has increased wages and pensions and subsidized electricity and gas bills, while showcasing Turkey’s homegrown defense industry and infrastructure projects. He also centered his reelection campaign on a promise to rebuild quake-stricken areas, including constructing 319,000 homes within the year. Many see him as a source of stability.

Kilicdaroglu is a soft-mannered former civil servant who has led the pro-secular Republican People’s Party, or CHP, since 2010. He campaigned on a promise to reverse Erdogan’s democratic backsliding, restore the economy by reverting to more conventional policies and to improve ties with the West.

In a frantic do-or-die effort to reach out to nationalist voters in the runoff, Kilicdaroglu vowed to send back refugees and ruled out any peace negotiations with Kurdish militants if he is elected.

Many in Turkey regard Syrian refugees who have been under Turkey’s temporary protection after fleeing the war in neighboring Syria as a burden on the country, and their repatriation became a key issue in the election.

Earlier in the week, Erdogan received the endorsement of third-place candidate, nationalist politician Sinan Ogan, who garnered 5.2% of the votes and is no longer in the race. Meanwhile, a staunchly anti-migrant party that had supported Ogan’s candidacy, announced it would back Kilicdaroglu.

A defeat for Kilicdaroglu would add to a long list of electoral losses to Erdogan and put pressure for him to step down as party chairman.

Erdogan’s AKP party and its allies retained a majority of seats in parliament following a legislative election that was also held on May 14. Parliamentary elections will not be repeated Sunday.

Erdogan’s party also dominated in the earthquake-hit region, winning 10 out of 11 provinces in an area that has traditionally supported the president. Erdogan came in ahead in the presidential race in eight of those provinces.

As in previous elections, Erdogan used state resources and his control of the media to reach voters.

Following the May 14 vote, international observers also pointed to the criminalization of dissemination of false information and online censorship as evidence that Erdogan had an “unjustified advantage.” The observers also said the elections showed the resilience of Turkish democracy.

Erdogan and pro-government media portrayed Kilicdaroglu, who had received the backing of the country’s pro-Kurdish party, as colluding with “terrorists” and of supporting what they described as “deviant” LGBTQ rights.

Kilicdaroglu “receives his orders from Qandil,” Erdogan repeatedly said at recent campaign rallies, a reference to the mountains in Iraq where the leadership of the outlawed Kurdistan Workers’ Party, or PKK, is based.

“We receive our orders from God and the people,” he said.

The election was being held as the country marked the 100th anniversary of its establishment as a republic, following the collapse of the Ottoman Empire.