Updated 16:15 EDT

Right-wing parties made such big gains at the European Union parliamentary elections Sunday that they dealt stunning defeats to two of the bloc’s most important leaders: President Macron of France and German Chancellor Olaf Scholz.

In France, the National Rally party of Marine Le Pen dominated the polls to such an extent that Mr. Macron immediately dissolved the national parliament and called for new elections, a massive political risk since his party could suffer more losses, hobbling the rest of his presidential term that ends in 2027.

In Germany, Mr. Scholz suffered such an ignominious fate that his long-established Social Democratic party fell behind the right-wing Alternative for Germany, which surged into second place.

Adding insult to injury, the National Rally’s lead candidate, Jordan Bardella, all of 28 years old, immediately took on a presidential tone with his victory speech at Paris, opening with “My dear compatriots” and adding “the French people have given their verdict, and it’s final.”

Mr. Macron acknowledged the thud of defeat. “I’ve heard your message, your concerns, and I won’t leave them unanswered,” he said, adding that calling a snap election only underscored his democratic credentials.

The four-day polls in the 27 EU countries were the world’s second-biggest exercise in democracy, behind India’s recent election. At the end, the rise of the right was even more stunning than many analysts predicted. The French National Rally stood at just over 30 percent, or about twice as much as Mr. Macron’s pro-European centrist Renew party that is projected to reach around 15 percent.

In Germany, the most populous nation in the 27-member bloc, projections indicated that the AfD overcame a string of scandals involving its top candidate to rise to 16.5 percent, up from 11 percent in 2019. In comparison, the combined result for the three parties in the German governing coalition barely topped 30 percent.

Overall across the EU, two mainstream and pro-European groups, the Christian Democrats and the Socialists, remained the dominant forces. The gains of the right wing came at the expense of the Greens, who were expected to lose about 20 seats and fall back to sixth position in the legislature.

For decades, the European Union had confined the hard right to the political fringes. With its strong showing in these elections, the right could now become a major player in policies ranging from migration to security and climate.

The Greens were predicted to fall from 20 percent to 12 percent in Germany, a traditional bulwark for environmentalists, with more losses expected in France and several other EU nations. Their defeat could well have an impact on the EU’s overall climate change policies, still the most aggressive across the globe.

The center-right Christian Democratic bloc of EU Commission President Ursula von der Leyen, which already weakened its green credentials ahead of the polls, dominated in Germany with almost 30 percent, easily beating Mr. Scholz’s Social Democrats, who fell to 14 percent, even behind the AfD.

“What you have already set as a trend is all the better — strongest force, stable, in difficult times and by a distance,” Ms. von der Leyen told her German supporters by video link from Brussels.

As well as France, the hard right, which focused its campaign on migration and crime, was expected to make significant gains in Italy, where Premier Giorgia Meloni was tipped to consolidate her power.

Voting will continue in Italy until late in the evening and many of the 27 member states have not yet released any projections. Nonetheless, data already released confirmed earlier predictions: the EU’s massive exercise in democracy is expected to shift the bloc to the right and redirect its future.

With the center losing seats to hard right parties, the EU could find it harder to pass legislation and decision-making could at times be paralyzed in the world’s biggest trading bloc.

EU lawmakers, who serve a five-year term in the 720-seat Parliament, have a say in issues from financial rules to climate and agriculture policy. They approve the EU budget, which bankrolls priorities including infrastructure projects, farm subsidies and aid delivered to Ukraine. And they hold a veto over appointments to the powerful EU commission.

The voting marathon began in the Netherlands on Thursday, where an unofficial exit poll suggested that the anti-migrant hard right party of Geert Wilders would make important gains, even though a coalition of pro-European parties has probably pushed it into second place.

Since the last EU election in 2019, populist or far-right parties now lead governments in three nations — Hungary, Slovakia and Italy — and are part of ruling coalitions in others including Sweden, Finland and, soon, the Netherlands. Polls give the populists an advantage in France, Belgium, Austria and Italy.