海角大神

This could be crunch time for the European Union.

As voters elect a new continent-wide parliament this week, both supporters of the European Union and its opponents are casting the poll as a defining moment for the future of the bloc 鈥� and perhaps for liberal democracy.

鈥淚t is for you to decide whether Europe, and the values of progress that it embodies, are to be more than just a passing episode in history,鈥� French President Emmanuel Macron wrote in an open letter to Europe鈥檚 400 million electors, warning them against far-right nationalists.

Mr. Macron鈥檚 chief rival and virulent EU critic Marine Le Pen, meanwhile, foresees 鈥渢he awakening of the people鈥� that will presage 鈥渁 Europe of free sovereign nations,鈥� as she declared at a weekend rally of European nationalists in Milan.

The rhetoric on both sides, designed to galvanize supporters, may be overblown. But the election will reveal just how strong the politicians seeking to undermine the EU really are. And they could win enough seats to stall the union鈥檚 integration drive, says Susi Dennison, an analyst with the European Council on Foreign Relations. 鈥淲e are coming to a crossroads.鈥�

The rise of the Europopulists

Starting on Thursday, over five days, European voters in 28 countries will take part in the second largest democratic exercise in the world, after India鈥檚 elections. They will choose the 751 members of the European Parliament, which has increasingly asserted its authority in recent years.

The parliament scrutinizes and votes on all legislation proposed by the EU鈥檚 executive, the European Commission. It often amends bills significantly. Members also have the power to name the commission鈥檚 president 鈥� the top job in Europe 鈥� and to oversee the EU budget.

For decades the parliament has been controlled by a 鈥済rand coalition鈥� of center-right and center-left political groups. At stake this year is 鈥渨hether the center holds,鈥� says Cas Mudde, a Dutch expert on populism who teaches at the University of Georgia in Athens, Georgia.

Opinion polls suggest that it probably can hang on, but with a weakened grip, by bringing in new partners. The two big centrist political families are projected to lose about 70 seats each; a variety of Europhobic parties are expected to pick most of them up and to control one-third of the parliament. These parties range from Euroskeptics dubious about the value of more integration to outright enemies of the whole idea of a European Union.

鈥淧eople are questioning the system and less likely to vote for the status quo,鈥� says Ms. Dennison. 鈥淎nti-European parties are doing well at presenting themselves as change.鈥�

Such anti-establishment parties have boomed since the last European elections in 2014, fueled by increasing economic inequality, an influx of migrants in 2015 and 2016, and a widespread sense among voters that their voices are not heard.

Right-wing populist parties have joined governments in Italy, Hungary, Poland, and Austria. The British exemplar of the trend, Nigel Farage鈥檚 Brexit Party, will win the European elections in the United Kingdom and Ms. Le Pen鈥檚 National Rally (formerly National Front) is running neck and neck with Mr. Macron鈥檚 party.

They feel the wind in their sails. 鈥淭hirty years ago we thought that Europe was our future,鈥� Hungarian Prime Minister Viktor Orb谩n 鈥� self-declared herald of 鈥渋lliberal democracy鈥� 鈥� told a meeting of his supporters last year. 鈥淭oday we believe that we are Europe鈥檚 future. Go for it!鈥�

鈥淎fter the elections,鈥� says Jan Techau, an analyst with the German Marshall Fund of the U.S., a Berlin-based think tank, 鈥渢he European Union will look like the new Europe鈥� where populist parties are prominent in almost every nation.

鈥楥hanging Europe from the inside鈥�

Until recently, almost all of them were advocating pulling out of the EU, or from its common currency, the euro. Not anymore. Withdrawal has not proven to be a vote-winning policy anywhere but Britain, because, despite the rising tide of identity populism, the EU is broadly popular with large majorities of voters across the continent. A recent Eurobarometer poll found that 68% of respondents thought membership in the bloc had been good for their country, the highest proportion since 1983.

So now, Matteo Salvini, deputy prime minister of Italy, head of his political party The League, and leader of an emerging European alliance of populist-nationalist parties, has adopted the same approach as most of his colleagues: to try to reform the EU.

With enough allies, Ms. Le Pen told foreign journalists earlier this year, 鈥渨e can legitimately envisage changing Europe from the inside, modifying the very nature of the European Union, because we are strong enough.鈥�

Where once the anti-EU forces used the European parliament mainly as a stage for their rhetoric, 鈥渘ow they see an interest in having a European project and they are thinking more strategically about how to work,鈥� says Ms. Dennison.

That could spell trouble from the start in a finely balanced parliament. If the anti-establishment parties work together 鈥渢hey will probably be able to frustrate and oppose further integration鈥� on the financial and other fronts, predicts Professor Mudde.

And if their representatives are elected in the numbers they are expecting, the pressure will be on rival pro-EU delegates 鈥� including Greens, Socialists, Conservatives, and Liberals 鈥� to work closely together. Whether such a broad spectrum of parties will be able to agree on matters like who should head the European Commission is still unclear.

Adding to the complications, national governments each nominate one of the 28 commissioners, the EU equivalent of ministers. Populist governments in Hungary, Poland, and Italy might choose to nominate candidates who do not share the union鈥檚 professed values and purposes, although the incoming president of the commission can turn a candidate down if he does not think the nominee could win parliamentary approval.

鈥淭he EU is a compromise machine,鈥� says Mr. Techau. If the next commission, the parliament, and the European Council (consisting of the heads of government) all include significant numbers of national-populist politicians, he points out, 鈥渢hat is going to get more difficult.鈥�

If she has her way, Ms. Le Pen says, 鈥渢hings will be turned completely upside down.鈥�

Nationalists of Europe, unite?

To be effective, though, the anti-Europeans will have to work as a disciplined alliance. Mr. Salvini has been seeking to build a unified group, but this will not be easy. Currently they remain divided among three different blocs in the parliament.

Steve Bannon, President Donald Trump鈥檚 former chief strategist, has been trying fruitlessly for months to unite Europe鈥檚 disparate national-populist forces into a single organization that he has called 鈥淭he Movement.鈥� But some are pro-American, others pro-Russian; some favor free markets, others lean toward protectionism; parties such as Mr. Orban鈥檚 Fidesz are aggressively 海角大神, the National Rally in France is deliberately secular.

鈥淚t is a long road to unity,鈥� acknowledges Ms. Le Pen.

But even disunited, the anti-establishment parties could prove a disruptive force in the parliament and beyond. 鈥淭he potential is there for the EU to eat itself from inside,鈥� says Ms. Dennison. 鈥淏ut this is not the end of the road. The battle will not be won or lost this time.鈥�

Dominique Moisi, a veteran political observer in Paris now advising the Montaigne think tank, who sees echoes of the 1930s in today鈥檚 rise of the far-right, agrees. 鈥淗istory is not yet written,鈥� he says. 鈥淗istory is hesitating.鈥�

鈥� Dominique Soguel in Milan contributed reporting to this article.