EPA Duda rises over Brussels The election of a Euroskeptical president raises questions about Warsaw’s sway in the EU.

The surprise victory of Andrzej Duda in Poland's presidential runoff was greeted with shock in Brussels, and raised pressing questions about the future of Warsaw's policies toward as well as influence in the EU.

The European capital had long factored in a second term for incumbent Bronisław Komorowski. Dismissed as an unknown and long-shot, Duda triumphed in Sunday's elections by three percentage points, heralding the resurgence of a more socially conservative and Euroskeptical strand of Polish politics.

The 43-year-old lawyer comes from the Law and Justice (PiS) bloc of Jarosław Kaczyński, a former prime minister who will lead the party — now brimming with momentum and confidence — into parliamentary elections in the autumn. Komorowski's loss reflected voter fatigue with his centrist Civic Platform (PO), which has ruled Poland since 2007 and comes into the election campaign on a weaker foot. This unexpected political shift is also forcing a rethink of Poland by its main EU partners, which view Warsaw as the leading EU power east of Germany.

“Duda is a representative of the Kaczyński movement, which was very critical of the common European approach and has a very nationalistic background,” said Manfred Weber, president of the center-right European People’s Party, the largest grouping in the European Parliament. “That is creating a lot of concern here.”

Under the Polish constitution, the president can veto laws and “on foreign policy cooperates with the prime minister,” who governs the country day-to-day. Even with the presidency’s limited powers, Duda’s arrival changes the mood in Warsaw as well as Brussels. The parliamentary election this fall will either blunt or confirm PiS’s return to the heart of power in Poland

The possible second coming of Kaczyński isn't going down well in Brussels. During his 16 months as prime minister, Kaczyński had terrible relations with Berlin. He used German wartime atrocities as a bargaining chip in EU negotiations, and was suspicious of any EU ideas that in his view would weaken Poland’s national sovereignty. His views on gay marriage and the death penalty were and remain out of the European mainstream.

Poland’s emergence as an EU power coincided with Kaczyński’s departure in 2007. A new tandem of Prime Minister Donald Tusk and Radek Sikorski, his Oxford-educated foreign minister, were embraced by Berlin. It helped too that Poland’s economy continued to outperform its neighbors. Poland was the only EU country to avoid recession since the onset of Europe’s economic crisis in 2009.

While Spain and Italy were distracted by their economic troubles and the UK was as usual debating whether it even wanted to be in the EU, Poland partnered with Germany on energy and other policies and sought to punch above its weight in the diplomatic arena, particularly on Ukraine and Russia. In Brussels, Poles snagged plumb posts.

A recent study of national “political muscle” by the Bruegel think tank found that Poland now holds the seventh-highest total of top-ranked EU jobs — just behind Belgium, which has home field advantage in Brussels. It is the only one of the “big six” EU countries (Germany, France, UK, Italy, Spain and Poland) to see an increase in the percentage of those jobs from 2009 to 2015. “The UK, Italy and Spain have all seen relative declines in their Commission and parliamentary appointments,” the study said.

Polish wave ebbing

The high point of that Polish wave was Tusk’s appointment as president of the European Council last year.

Yet even before Duda became a Polish household name, Warsaw’s influence in Brussels was ebbing, observers say. In recent months, Italy has shaken off some of its political torpor and chaos under the energetic new prime minister, Matteo Renzi. Spain’s economy is recovering, and Madrid is now angling for prestigious jobs like head of the Eurogroup of eurozone finance ministers.

“You know with waves — they rise and then they fall,” said a senior Polish official at the European Commission who requested anonymity.

Tusk's departure from Warsaw brought to power Ewa Kopacz, a former health minister with little Brussels exposure or political charisma. The multilingual Sikorski became speaker of parliament, leaving the top diplomat’s post to Grzegorz Schetyna, a PO party baron who had shown no prior experience in foreign affairs.

At the very least, Poland’s political elites will be for the coming months consumed by campaigning, leaving little time for EU matters. “Of course all the attention is going to be on national politics,” said Mikołaj Dowgielewicz, a former Europe minister now with the Council of Europe Development Bank. “Poland’s place in the EU will be determined after the parliamentary elections.”

It is the possible reappearance of Kaczyński, who is 65, that causes far more consternation among Eurocrats than Duda. The lawyer from Kraków is an MEP (he is currently closing up his office) who hasn’t been vocally hostile to the EU, although PiS does belong to the European Conservatives and Reformists bloc, which is cool towards ambitious federalist ideas. “He hasn’t given the impression that he is a Euroskeptic,” said Andreas Schwab, a member of the EPP, which also includes Civic Platform.

Duda doesn’t seem to share Kaczyński’s coolness toward Germany. His wife, Agata Kornhauser-Duda, is a German language teacher in Kraków. “I don’t think he is personally anti-German,” said Marcin Zaborowski, head of the Warsaw-based Polish Institute of International Affairs. “Until the parliamentary elections the party will be fighting for centrist voters so it won’t emphasize that radical anti-German view. But the party does have a lot of anti-German stereotypes.”

The issue for Duda in Warsaw and in Brussels is how closely he will be tied to Kaczyński, a domineering politician who has shown little past tolerance for rivals. Duda has already announced that he is resigning from PiS — it is something of a tradition for Polish presidents to claim they are above party politics — but Kaczyński’s influence still looms large.

“Kaczyński steered the campaign. Please believe me, these were the decisions of Jarosław Kaczyński,” one of his top lieutenants Mariusz Kamiński told Poland’s RMF FM radio this week.

Kalina Oroschakoff and Maïa de la Baume contributed to this article.