This time, the pundits said, the National Front was finally going to break the "glass ceiling" and score above 40% of the popular vote. Yet "Marine," as she wanted everyone to call her, didn't even quite reach 34%.
In her concession speech, she announced to the hundreds of partisans gathered at the Chalet du Lac at Vincennes that, after "the great gains" achieved since the last time there was a National Front candidate in the second round (her father, who scored 18% of the vote in 2002
against Jacques Chirac), she was going to rebuild the party entirely. This would even include changing its name.
But it is possible that her swift attempt to re-brand the party by changing its name is an effort to seize the initiative before her detractors start bringing up her campaign mistakes try to get rid of her.
Throughout her early campaign she was, if anything, too subdued. Then, after reaching the second round, she adopted a Trump-like manner: blustery and aggressive, which was never more in evidence than at last Wednesday's debate.
The French of all social classes want a respectable president -- someone who will make the country look good.
Yet having cultivated a more mainstream image, after a three-hour contest in which she flubbed her lines and quoted fake news, "Marine" was back to being a "Le Pen": a toxic brand she'd been at pains to normalize
that six years ago, she even excluded her father from the party he founded.
But who could take over from Marine? The party only has two MP's: Gillbert Collard and Le Pen's own niece, Marion Maréchal Le Pen, 27, who seems the most obvious choice.
Marion is everything her aunt isn't: controlled, cool, competent and a workhorse. She also is a traditional Catholic, closer to those parts of the French hard right than her aunt, who appeals to working-class, former Communist voters.
Marion has protested that she is loyal to her aunt — together, they manage to appeal to a wide spectrum, from Marine's rust-belt northern constituency to Marion's southeastern one in Vaucluse, where resentment of immigration is the strongest.
Marion has even suggested that she could leave politics altogether. The reaction among the faithful after the debate fiasco was that Marion would have been a much more capable debater. Maybe they will decide that now is the time for her to step up -- although it is unlikely that she will do so before the party faces its next major test: the French parliamentary elections in six weeks.
For years, the Front has complained about the "unfair" first-past-the-post system, and it's true that two measly MPs hardly represent the party's real presence on the ground.
But another poor showing in the parliamentary elections will leave many wondering: is the National Front a real political party yet, or only a fleshed-out Le Pen cult?
The party has grown and enjoyed success in regional and European elections in 2014 and beyond. But an AFP report from 2016 suggested
that in just two years, 28% of the lawmakers elected in 2014 had resigned, citing chaos in the party as the reason.
This kind of chaos is fine for a fringe party of troublemakers. But now that the Front has blown a serious chance to become the undisputed French opposition, the stakes are now much higher for the party — and for Marine Le Pen.