Francois Fillon’s surprising victory in the Republican primaries has sent his future rivals scrambling to change course.

Remi Piet is a research associate on political economy and foreign policy at the Florida International University.

More than four million members of The Republicans turned up to elect their champion for the 2017 French presidential elections.

Francois Fillon emerged as the winner, confirming his leadership of The Republicans at the second round of the conservative primary election in France.

While pollsters had continuously forecasted a face-off between Nicolas Sarkozy and Alain Juppe in the second round, Fillon had surprised many by securing more than 40 percent of the votes in the first round. His second victory faced no contestation; Juppe conceded defeat a few minutes after it turned out his opponent had gathered two thirds of the votes on Sunday.

The outcome of the Republican primaries revealed a desire among the French people for new faces. Although Fillon started his political career more than 40 years ago, he is ironically considered a newcomer because he was kept in the shadows during the Sarkozy administration.

His victory has not only stirred up The Republicans but it also pushed his future rivals to scramble to change their strategies for the 2017 elections.

A grassroots movement

Opinion polls over the past year have been consistent in forecasting an eventual victory of the Republican candidate, making Francois Fillon a frontrunner to enter the Elysee Presidential Palace next year.

With a Socialist Party washed up after five years in office and a xenophobic National Front party structurally unable to gather support beyond its traditional electorate, the two-round election system in France favours political changeover and mainstream parties.

As a result, The Republicans primary ballot was the opportunity to choose who would face and potentially defeat Le Pen in the second round of the presidential elections six months from now.

On many societal issues, Fillon appeared as a milder, more reasonable version of Le Pen which could be very challenging for her presidential hopes.

Nevertheless, one of the main lessons to learn from this primary is that pollsters are often wrong. None of them correctly estimated the strong support that Fillon gathered by campaigning relentlessly on the ground, while Sarkozy or Juppe had relied mainly on Parisian debates and television appearances.

Fillon’s victory is the result of his capacity to create a grassroots movement among The Republicans that supported concrete and radical policy options over the populistic speeches of his former boss, Sarkozy.

It also revealed a determination among Republican sympathisers to elect a candidate who focuses on the party’s core values of economic liberalism and social conservatism, rather than on building a bipartisan and moderate platform, as Juppe tried.

Multidimensional campaign game

The Socialist Party will hold its primaries next February while the candidates for the Communists, Jean-Luc Melenchon, Greens, Yannick Jadot, and far-right National Front, Marine Le Pen, are already known.

President Hollande and the Socialist Party were hoping for a Sarkozy victory. His programme, they thought, would have antagonised moderate voters.

On the other hand, Marine Le Pen and the National Front were rooting for the more moderate Alain Juppe to win, allowing the National Front to attract the more conservative Republicans. The choice of Fillon is far less convenient for both Hollande and Le Pen.

In particular, Fillon’s strong conservatism is reflected in his ideas on social policies. His Catholic background and hardliner position with regards to same-sex marriage, immigration and – even at times – abortion rights have made him the preferred candidate of a traditionalist and religious electorate that Le Pen was hoping to grab.

On many societal issues, Fillon appeared as a milder, more reasonable version of Le Pen which could be very challenging for her presidential hopes.

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As a result, the National Front is now changing its campaign strategy and will probably attack the Republican candidate on the economic front instead, a dimension where Le Pen is much less at ease, with unrealistic, proposals and a flagrant lack of experience.

Moreover, the choice of a significantly more conservative candidate by the Republican Party offers a larger space for the Socialist Party at the centre of the political spectrum.

As President Hollande still hesitates to run for re-election in light of his abysmal approval ratings, current Prime Minister Manuel Valls is most likely to be very satisfied by Fillon’s victory. If anointed by the upcoming Socialist primary, Valls would probably make strides within a moderate electorate dissatisfied with Fillon’s position on social issues.

The same calculations were probably made by the former Minister of the Economy Emmanuel Macron, who confirmed his run for the presidency.

The economy aspect

In the economic arena, the extremely liberal project defended by Fillon might not resound with the French population, traditionally attached to their welfare state system. Often described as a disciple of Thatcher, he has proposed to slash civil servant jobs, expand further economic deregulation and raise the retirement age significantly.

Among the other candidates in the Republican primary, he had the most ambitious economic reforms agenda. He suggested to cut taxes on the wealthiest citizens drastically, while privatising part of the healthcare system.

These propositions might remobilise the left-wing electorate or encourage more moderate candidates such as Francois Bayrou from the Democratic Movement who came third in the 2007 elections.

Bayrou – a likely option for the position of prime minister had Juppe won the Republican primaries – has confirmed his new interest for a candidacy that could severely split the right-wing votes.

The upcoming weeks will be interesting to watch as other parties’ candidates emerge. Fillon’s final victory is far from being set in stone.

Remi Piet is a research associate on political economy and foreign policy at the Florida International University.

The views expressed in this article are the author’s own and do not necessarily reflect Al Jazeera’s editorial policy.