With two weeks left before the May 7 runoff, Macron is seeking to hold on to centrist voters, while Le Pen has doubled down on her anti-immigrant rhetoric.
To broaden her appeal to voters, Le Pen announced Monday that she is temporarily stepping down as head of her far-right party. “Tonight, I am no longer the president of the National Front,” she said on French television. “I am the presidential candidate.” The move appeared aimed at reaching out to leftists who share some of her positions, notably her aversion to membership in the E.U. and NATO.
Never in the six-decade-long history of the modern French state have the traditional parties been barred from the presidency. And never before has the National Front — once considered an extremist fringe with no chance of gaining power — received more than 20 percent of the vote in a presidential election.
The choice between Macron and Le Pen is ultimately a choice between two radically different visions of the euro zone’s second-largest economy and only nuclear power.
"You really have two new parties," said Dominique Moïsi, a French political scientist and author of "The Geopolitics of Emotion," a study of how subjective undercurrents can alter political life. "On the one hand, you have global openness, based on hope. On the other, you have a party of nationalistic closure, based on fear."
After terrorist attacks that have rocked France in the past two years, Le Pen on Monday promised, for the first time, that she would expel all “foreign Islamists” — no longer just those suspected of crimes. Meanwhile, leaders across the political spectrum were quick to fan the flames of fear, too, warning that Le Pen might win.
“This is deadly serious now,” Socialist candidate Benoît Hamon said in his concession speech Sunday night as he urged his supporters to back Macron in the runoff. François Fillon, the mainstream conservative contender, said much the same.
Financial markets and pro-European political groups showed clear signs of relief that Macron had emerged on top in Sunday's vote and appeared to hold a strong position ahead of the two-person runoff. But Macron's backers acknowledged the risky dynamic, even as they embraced opinion polls that show him with a commanding lead over Le Pen.
“It’s necessary to be humble. The election isn’t won. We must regroup,” Richard Ferrand, general secretary of Macron’s political movement, said on France’s BFM television news channel.
But the observation came only after Macron was criticized for delivering a victory speech Sunday night — followed by a celebratory banquet in a posh Paris restaurant — that suggested to many that he considered the battle over.
"The French people have expressed themselves," Macron declared in his remarks, before a roaring crowd . "The power of the momentum behind me will be the key to my ability to lead and to govern."
In any case, not all of those defeated in the first round responded to the call of the “Republican Front,” a bipartisan coalition devoted to thwarting a National Front victory at all costs.
Le Pen complained Monday that political elites were conspiring against her, just as they had united against her father, Jean-Marie Le Pen, in the final round of the 2002 presidential vote. In that contest, when the elder Le Pen, a convicted Holocaust denier, defied all odds and qualified for the runoff, leftists turned out to vote for Jacques Chirac, the incumbent conservative president.
“The old rotten Republican Front, that no one wants anymore and that the French have kicked out with exceptional violence, is trying to unite around Mr. Macron,” Marine Le Pen said during a stroll through a market in the northern town of Rouvroy, reiterating that French voters would not be deceived.
“This is a referendum for or against wild globalization,” she said, passing out fliers that said “Eradicate Islamist terrorism.”
Many of those who embraced Macron did so out of concern, not enthusiasm. As Fillon put it: “Abstention is not in my DNA, especially when an extremist party comes close to seizing power.”
In the ongoing war over national identity, Macron faces considerable obstacles. Whether on the far left or the far right, populist voters who want to overhaul the “system” accounted for 49.8 percent of the ballots cast Sunday. And his better-days-are-before-us stump speech has at times been perceived as disconnected from the grim mood in France, which is struggling with a stagnant double-digit unemployment rate, the threat of terrorism and Europe’s refugee crisis.
But Macron defends the “system” and vows to improve it. His centrist vision — “neither of the right, nor the left,” in his words — calls for strong E.U. nations to do more to support weaker ones. He would embrace immigrants and refugees and would enact business-friendly reforms to make it easier to hire and fire workers.
If Macron ascends to the hallowed halls of the Elysee Palace but falters once there, Le Pen could return stronger than ever in 2022. Already, she has outperformed her 2012 presidential performance as well as that of her father in his 2002 runoff.
Meanwhile, France’s two traditional mainstream parties were left confronting their failures. Hamon captured just 6.4 percent of the vote on Sunday, a remarkable meltdown of support, given that Socialist François Hollande is the incumbent president.
“Undoubtedly, it’s the end of a cycle, the end of a story,” said former Socialist prime minister Manuel Valls, who broke with his party to endorse Macron ahead of the first round.
Virgile Demoustier in Paris and Brian Murphy and William Branigin in Washington contributed to this report.