PARIS — Voting is underway in mainland France on Sunday in pivotal runoff elections that could hand a historic victory to Marine Le Pen’s National Rally and its inward-looking, anti-immigrant vision — or produce a hung parliament and political deadlock.

French President Emmanuel Macron took a huge gamble in dissolving parliament and calling for the elections after his centrists were trounced in European elections on June 9. The snap elections in this nuclear-armed nation will influence the war in Ukraine, global diplomacy and Europe’s economic stability, and they’re almost certain to undercut Mr. Macron for the remaining three years of his presidency.

The first round on June 30 saw the largest gains ever for the anti-immigration, nationalist National Rally, led by Marine Le Pen. A bit over 49 million people are registered to vote in the elections, which will determine which party controls the 577-member National Assembly, France’s influential lower house of parliament, and who will be prime minister. 

If support is further eroded for Mr. Macron’s weak centrist majority, he will be forced to share power with parties opposed to most of his pro-business, pro-European Union policies. Voters at a Paris polling station were acutely aware of  the far-reaching consequences for France and beyond.

“The individual freedoms, tolerance and respect for others is what at stake today,” said a 45-year-old voter who works in advertising, Thomas Bertrand.

Racism and antisemitism have marred the electoral campaign, along with Russian cybercampaigns, and more than 50 candidates reported being physically attacked — highly unusual for France. The government is deploying 30,000 police on voting day.

The heightened tensions come while France is celebrating a very special summer: Paris is about to host exceptionally ambitious Olympic Games, the national soccer team reached the semifinal of the Euro 2024 championship, and the Tour de France is racing around the country alongside the Olympic torch.

As of noon local time, turnout was at 26.63 percent, according to France’s Interior Ministry, slightly higher than the 25.90 percent reported at the same time during the first round last Sunday.

During the first round, the nearly 67 percent turnout was the highest since 1997, ending nearly three decades of deepening voter apathy for legislative elections and, for a growing number of French people, politics in general. Macron cast his ballot in the seaside resort town of La Touquet, along with his wife Brigitte. Prime Minister Gabriel Attal voted earlier in the Paris suburb of Vanves.

Ms. Le Pen is not voting, because her district in northern France is not holding a second round after she won the seat outright last week. Across France, 76 other candidates secured seats in the first round, including 39 from her National Rally and 32 from the leftist New Popular Front alliance. Two candidates from Macron’s centrist list also won their seats in the first round.

The elections wrap up Sunday at 8:00 p.m. (1800 GMT) in mainland France and on the island of Corsica. Initial polling projections are expected Sunday night, with early official results expected late Sunday and early Monday.

Voters residing in the Americas and in France’s overseas territories of Saint-Pierre-et-Miquelon, Saint-Barthélemy, Saint-Martin, Guadeloupe, Martinique, Guyana and French Polynesia voted on Saturday.

Associated Press