(Bloomberg) — Finland is holding a presidential election on Sunday, where NATO’s newest member votes for a top diplomat and supreme commander for its defense forces to guard the alliance’s longest stretch of border against its main adversary, Russia.

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Voting started at 9 a.m. local time Sunday. While no exit polls are published, about 44% of those entitled to vote cast their ballots in advance, and first results will be released when polling stations close at 8 p.m.

The leadership contest is the most riveting in decades as three presidential candidates are in a tight race to succeed President Sauli Niinisto, 75, who is no longer eligible to run after serving two consecutive six-year terms.

The president’s role in leading Finland’s foreign policy grew in significance during Niinisto’s second term after Russia’s unexpected all-out invasion of Ukraine in early 2022, which fundamentally altered Europe’s security calculus. After a radical rethink, Finland joined the North Atlantic Treaty Organization last year.

Former Prime Minister Alexander Stubb, previous Foreign Minister Pekka Haavisto and Speaker of parliament Jussi Halla-aho, who hails from the populist Finns Party, top the polls ahead of the first round of voting. While their views on foreign policy are largely aligned, their proximity to each other has electrified the race and means a second round on Feb. 11 is almost certain, pitting the top two against each other.

Trailing the trio are Finland’s central bank Governor Olli Rehn, followed by EU Commissioner Jutta Urpilainen, among a total of nine candidates.

The one seen as the most adept at steering foreign and security policy will likely appeal to the electorate. The next president will ultimately have to focus on deepening and molding Finland’s role in NATO, guarding half of the bloc’s border with Russia. The Nordic country has one of Europe’s strongest armies, configured to fight a major land campaign and has 280,000 reserve troops. Eight in ten Finns say they’re ready to defend their nation if attacked.

Niinisto will be a tough act to follow. The seasoned diplomat met world leaders regularly, with Finland punching above its weight on the global stage under his stewardship. His legacy will be as the one who led his country into the defense alliance that’s grown stronger and larger after Russia launched its offensive in Ukraine in 2022.

Read More: Finland Joins NATO as Defense Alliance Expands Northward

Finland’s military alignment prompted Russia to threaten a response, and tensions on the 1,300-kilometer (800-mile) border are already rising. A hybrid operation has been underway since November, with Russian authorities assisting asylum seekers to the demarcation in what Finland calls “weaponized immigration” to put pressure on the government in Helsinki. That’s led Finland to close the frontier entirely.

Bloomberg asked the candidates for their foreign-policy priorities.

Alexander Stubb, 55

The former prime minister has held all the top ministerial posts in Finland, including the finance and foreign affairs portfolios. Most recently a professor at European University Institute in Florence, Italy, Stubb has a PhD in international relations.

“We are now finally a member of the strongest military alliance of the world,” he said. “We have doubled NATO’s border to Russia. It is our duty and obligation to maintain a strong defense and take of security in our corner of the world.”

Pekka Haavisto, 65

The veteran diplomat and Green Party politician steered Finland into NATO as foreign minister, navigating sensitive negotiations to make membership a reality. Haavisto, who is running for president for a third time, is the only out gay candidate in the race.

His priority: “to assure broad western and global support to Ukraine in its fight against the Russian war of aggression.”

Jussi Halla-aho, 52

Currently the speaker of Finland’s parliament and a former leader of the nationalist Finns Party, Halla-aho is known for his hardline stance on immigration but appeals to voters disappointed with the established parties. He takes a stronger stance on Russia than fellow candidates and has made a personal donation to have his message painted on the side of a rocket in support of Ukraine. Halla-aho gave a speech in fluent Ukrainian at the parliament in Kyiv last year, leveraging his linguistics education focused on Slavic languages.

Olli Rehn, 61

The Governor of the Bank of Finland earned his credentials steering eurozone economic policy as commissioner during the debt crisis years, having previously overseen the European Union’s enlargement portfolio.

For Rehn, “the top no. 1 priority is to maintain peace and security for Finland, which means finalizing the integration of Finland to the western security alliance through our NATO membership and defense cooperation agreement with the US,” he said. “At the same time it’s essential that we maintain a very strong national defense capability.”

Jutta Urpilainen, 48

The European Commissioner for International Partnerships and — a decade ago — Finland’s first female finance minister entered the race later than other candidates and represents the Social Democratic Party.

“The Finnish president’s top priority should always be preserving and enforcing peace and stability in Finland,” Urpilainen said. “That objective must be pursued on several fronts, including credible national defense, close bilateral relations with key allies, constructive participation in relevant international organizations and active engagement in multilateral efforts to tackle global challenges, especially climate change.”

–With assistance from Rob Dawson.

(Updates with start of voting, turnout in advance ballots in second paragraph)

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