For Marine Le Pen’s supporters, the European Union is an abomination that violates national sovereignty and opens borders to mass immigration, while the eurozone prevents the French government from controlling its economic and monetary policy. To Mr. Macron, the European Union is the institution that can help France be a player and defend itself in a globalized world, while its open borders and common currency increase economic opportunities for its citizens. Basically, Europeans are stronger together.

This is the clear choice French voters will face in the second round on May 7. A choice between two starkly different visions of Europe, between two opposite outlooks on the world: an open world versus a world of borders and barriers, modernity versus conservatism. The political consensus, based on the European project and liberal values, that allowed two major mainstream parties to govern France alternately on the right and the left for the past three decades has been shattered.

The candidate of the governing Socialist Party, Benoît Hamon, earned a devastating 6.4 percent of the vote, mirroring a trend in some other European countries. As for Les Républicains, the center-right party, it is also in deep trouble. Their candidate, former Prime Minister François Fillon, came in third on Sunday with 20 percent. Never before had the major party of the right been eliminated from the second round.

Would the party have fared better with a candidate who hadn’t employed his wife in lucrative but elusive tasks and who paid for his own suits? Even this is not sure, such is the thirst for renewal and the furor of “dégagisme” (“scram-ism”), as the far-left candidate Jean-Luc Mélenchon, who claimed 19.6 percent, called the anti-politician trend — only to fall victim of it, too.

This is the new landscape, shaped by the steady rise of the National Front and euroskepticism over the past decade. Rather than hiding behind it, Emmanuel Macron chose early in his campaign to fly the European flag. He astonished his rivals by winning support for the European Union, against all odds, at his rallies. And it worked.

He also managed to reverse the fear factor: By the end of the campaign, polls showed that more than two-thirds of French voters, still convinced of the benefits of a common currency, did not want to leave the eurozone, throwing Marine Le Pen’s anti-euro agenda off balance. Mr. Macron embraced the French-German relationship, so vital to a unified Europe, and went to Berlin to meet Chancellor Angela Merkel, for whose immigration policy Marine Le Pen has only scorn.

Here is Mr. Macron’s toughest challenge in the next two weeks: how to reconcile an electorate that has grown more conservative and fearful of the effects of globalization with the idea that a stronger Europe is congruent with France’s interests and will not harm the country’s national identity. His frequent use of the words “protection,” his rousing calls to “patriots,” the French flags waving alongside the blue European banner with its gold stars at his rallies while supporters join him in singing “La Marseillaise,” show that he is aware of the danger of leaving the monopoly of patriotism to the National Front.

But even if he succeeds on May 7, he will still be left with other difficulties. Winning the June parliamentary elections — without a proper party — and achieving a majority to govern is one. Transforming the political system, as he has promised, to adjust it to the 21st century and give a voice to those voters who have felt excluded for so long is another. For a political novice, however talented and lucky, this is quite a tall order. But it is the condition for the dikes to continue holding up.