The far right was at the gates of power.

In the initial round of voting on June 30, Marine Le Pen’s National Rally came first with 33 percent support, topping more than half the local races. With the party projected to fall just short of an absolute majority, France was in a frenzy of speculation and anxiety. National Rally’s lead candidate, the 28-year-old Jordan Bardella, insisted that he’d agree to become prime minister only if he had Parliament behind him. On the evidence of the polls, he seemed well placed to demand a mandate.

But Sunday’s second round proved him wrong. Mr. Bardella not only fell far short of winning the prime minister’s office; his party came in third, with 143 seats. Although an expansion from its previous tally of 89, this was a far cry from what was projected just days ago. President Emmanuel Macron’s coalition, which had lagged throughout the short campaign, flouted expectations to come in second, with 168 seats. The biggest surprise was who came in first. The left-wing New Popular Front, a coalition of four parties hastily put together before this election, emerged as the largest force, with 182 seats.

This is a truly astounding result. Through a stunning act of collective responsibility, the far right has been stopped. But France is not suddenly fixed. With no group taking more than one-third of the National Assembly’s 577 seats, there is trouble ahead. The far right, though chastened, is in a stronger position than ever before, commanding a growing electoral coalition and decently placed for the presidential election in 2027. But France, on the back of pragmatic collaboration between parties and enthusiastic resistance from voters, has won a brilliant reprieve.

Cooperation among National Rally’s opponents was central to the turnaround. After the first round, over 200 third-place candidates from the New Popular Front and Mr. Macron’s coalition stood down, allowing other candidates clear runs. In what the Green leader Marine Tondelier called a “new republican front,” nodding to the tradition of French voters combining to thwart the far right, voters were asked to back whoever could beat the National Rally candidate.

They answered the call, left-wing voters especially. According to a poll, in duels in which either Mr. Macron’s allies or conservatives faced National Rally, seven in 10 left-wingers turned out for the anti-Le Pen candidate, with most others abstaining. The front held less well in duels between the left and Ms. Le Pen’s party: About half of Mr. Macron’s supporters backed the left, and one in six voted for the far right. The result, though, was stark. In seat after seat, the far right’s strong position wasn’t enough to overcome its combined opponents.

The strength of this mobilization was especially remarkable, given the mixed messages from government figures. In the days after the first round, the president’s camp split between those who called for a vote for any anti-Le Pen candidate and others who refused to stand down in favor of Jean-Luc Mélenchon’s France Unbowed — the biggest and most radical force on the left. Many on the center–right called on voters to block both Mr. Mélenchon and Ms. Le Pen, undermining the suggestion that the main issue was to stop the far right.

The New Popular Front is far from united. Mr. Mélenchon — who does not have a seat in Parliament — has tumultuous relations with the center-left Socialists and Greens, as well as the Communists, who will all want to avoid his taking the lead. On Sunday night, center-left figures in this camp gestured toward the need for broader dialogue and a change of political culture, already hinting at a rapprochement with Mr. Macron and a split with the more radical left. The New Popular Front, with barely a moment to enjoy its success, may soon begin to splinter.

From NYT