PARIS — Far-right leader Marine Le Pen vowed Sunday to overhaul her National Front party after a resounding defeat in France's presidential election, flagging a debate to come about the reasons for her defeat that could tear the party along ideological lines.

In her concession speech, Le Pen at first kept to the defiant tone of the campaign, underscoring that she had won an estimated 11 million votes in the runoff, more than ever before for the National Front. She warned that her followers were worried about a five-year Emmanuel Macron presidency, accusing him of representing "continuity."

But as Le Pen turned to the next big political challenge — parliamentary elections coming up in June — she sounded more conciliatory.

After months of attacking rivals during a bitter campaign, the Euroskeptic candidate gave a first hint of self-doubt, by saying her party was due for a "profound transformation" that she would lead in person.

“The National Front must also renew itself,” Le Pen told supporters near Paris as projected election results showed her losing by 34.5 percent to Macron’s 65.5 percent. “I will, therefore, start the process of a deep transformation of our movement … I call upon all patriots to join us.”

In the post-mortem to come, Le Pen's unrelenting opposition to Europe is bound to take center-stage.

The defeated candidate, who had predicted that a "populist wave" would submerge continental Europe after Britain's Brexit vote and the election of Donald Trump in the United States, offered no detail about the changes to come.

Florian Philippot, the party's influential vice president and architect of its anti-EU policy, said the National Front was bound to rename itself to reflect its ambition of gathering support beyond the party faithful. (Another senior aide, Nicolas Bay, said a name-change would be part of an internal debate.)

“Marine Le Pen said it clearly: 'The National Front will change,'” said Philippot. “It’s going to change into a new political force which, necessarily, will not have the same name.”

Lost opportunities

But neither Le Pen nor her chief political adviser addressed the causes of Sunday's result which many, including her popular niece Marion Maréchal Le Pen, will find deeply disappointing.

The younger Le Pen had said her aunt should win "at least" 40 percent of the vote to put the party in good stead ahead of parliamentary elections — a target she missed by a long shot.

In coming weeks, the National Front will start to examine why Le Pen, who had equal speaking time with her rival on national networks, failed in her bid for power despite a cascade of factors that could favor her campaign: including terrorism on the Champs Élysées and a last-minute dump by hackers of documents stolen from Macron's campaign. (French electoral law forbade any direct discussion of the emails' content over the weekend but no damaging material emerged from the social media accounts of foreign anti-Macron activists.)

According to party insiders, there were problems in the campaign. Some told POLITICO they had lost any hope of victory after Le Pen's performance in a presidential debate against Macron. The candidate mixed up facts, floundered during questioning about her euro policy and attacked her opponent instead of arguing for her own victory.

"The debate was fatal for her," said the operator of one popular pro-Le Pen Twitter account.

Le Pen also missed a chance to broaden her appeal by winning over disappointed conservative voters, who were furious over the exit of their candidate, former Prime Minister François Fillon, in the first round. A senior aide said the party had failed to "work hard enough" on the campaign and adapt its strategy in the final dash.

Too Euroskeptic?

But one issue perhaps more crucial than any other to understanding her defeat was Le Pen's refusal to back down on plans to leave the EU, which poll after poll showed were rejected by most voters. While Le Pen focused far less on plans to hold a referendum on EU membership during this campaign, she never broke with the proposal completely.

In the post-mortem to come, Le Pen's unrelenting opposition to Europe is bound to take center-stage — with particularly Euroskeptic aides like Philippot in the firing line.

Some senior aides are known to be opposed to the Euroskeptic position. Election strategist Nicolas Bay and Gilbert Collard, one of two National Front MPs, have both previously said they wanted to have a debate about the euro exit plan.

Marion Maréchal-Le Pen, who plans to run for reelection as an MP in June, was never a vocal supporter of the anti-EU strategy, focusing instead on traditional values and a defense of French identity that were palatable to far-right voters in the south of France. She is the nominal leader of a southern-based current inside the National Front that is frankly opposed to the statist, anti-European line defended by Philippot.

After Sunday, the voices of Bay, Collard and Marion Maréchal-Le Pen will be heard more clearly in the National Front. Le Pen is unlikely to depart as party leader, despite stepping down temporarily as its president during the campaign. Support for her party is too wrapped up with the Le Pen family name to risk changing its figurehead, no matter how bad the defeat.

But Le Pen will have no choice but to listen to critique and start working on her next move.

Polls show her party winning just 15-20 seats in the parliamentary vote: an increase on her last run, but not enough to support her claims of becoming the country's "No. 1" political opposition to President Macron.

(POLITICO was one of several media outlets not granted access to the National Front's election-night event. Other outlets including daily Le Monde and Libération announced they would not cover the event in support of media that were kept out.)