France is the 27-member bloc's second economy, the only one with a UN Security Council veto, and its sole nuclear power. And as Russian President Vladimir Putin carries on with the war in Ukraine, French power will help shape Europe's response.
Twelve candidates are vying for the presidency -- including incumbent and favorite President Emmanuel Macron who is seeking a new term amid a challenge from the far-right.
Here's why the French election, taking place in two rounds starting Sunday, matters:
NATO
Russia's war in Ukraine has afforded Macron the chance to demonstrate his influence on the international stage and burnish his pro-NATO credentials in election debates. Macron is the only front-runner who supports the alliance while other candidates hold differing views on France's role within it, including abandoning it entirely. Such a development would deal a huge blow to an alliance built to protect its members in the then-emerging Cold War 73 years ago.
Despite declaring NATO's "brain death'' in 2019, the war in Ukraine has prompted Macron to try and infuse the alliance with a renewed sense of purpose.
"Macron really wants to create a European pillar of NATO,'' says Susi Dennison, Senior Fellow at the European Council on Foreign Relations. "He's used it for his shuttle diplomacy over the Ukraine conflict.''
On the far-left, candidate Jean-Luc Melenchon wants to quit NATO outright, saying that it produces nothing but squabbles and instability. A NATO-skeptic President Melenchon might be a concern, especially for Poland, which has a 1,160-kilometer border with the territory now controlled by Russia.
Several other candidates want to see either diminished engagement with the alliance or a full withdrawal. Although unlikely, France's departure from NATO would create a deep chasm with its allies and alienate the United States.
EUROPEAN COOPERATION
Observers say Macron's re-election would spell a real likelihood for increased cooperation and investment in European security and defense, especially with a new pro-EU German government.
Under Macron's watch, France's defense spending has risen by (euro)7 billion euros ($7.6 billion) with a target to raise it to 2% of gross domestic product -- something that leaders including Putin are watching closely. In his second term, Macron would almost certainly want to build up a joint European response to Ukraine and head off Russian threats.
A FAR-RIGHT ALLIANCE?
This election could reshape France's post-war identity and indicate whether European populism is ascendant or in decline. With populist Viktor Orban winning a fourth consecutive term as Hungary's prime minister days ago, eyes have now turned to France's resurgent far-right candidates -- especially National Rally leader Marine Le Pen who wants to ban Muslim headscarves on streets, and halal and kosher butchers, and drastically reduce immigration from outside Europe.
"If a far-right candidate wins, it could create some sort of alliance or axis in Europe," said Dennison, of the European Council on Foreign Relations. "Le Pen has been tweeting pictures of herself shaking hands with Orban in recent days. She is championing a Europe of strong nation-states."
That axis might include Poland's President Andrzej Duda, a right-wing populist and ally of Donald Trump. It has alarmed observers.
"Over 30 percent of French voters right now say they are going to vote for a far-right candidate. If you include Melenchon as another extreme, anti-system candidate, that's almost half the entire voting population. It is unprecedented,'' Dennison said.
Far-right candidate Eric Zemmour has dominated the French airwaves with his controversial views on Islam in France and immigration.
However, even centrist Macron ruffled feathers in Muslim countries two years ago when he defended the right to publish cartoons of the prophet Muhammad. That came during a homage to a teacher beheaded by a fundamentalist for showing the cartoons to his pupils as part of a class on free speech.
A FRIEND OF AMERICA
The US often touts France as its oldest ally -- and from Russian sanctions to climate change and the United Nations, Washington needs a reliable partner in Paris. France is a vital trans-Atlantic friend for America, not least for its status as continental Europe's only permanent UN Security Council member wielding veto power.
Despite the bitter US-France spat last year over a multibillion deal to supply Australia with submarines -- which saw France humiliated -- President Joe Biden and Macron are now on solid terms.
"Macron is obviously the only candidate that has history and credentials in the US relationship. All the others would be starting from scratch at a time of great geopolitical uncertainty,'' said Dennison...
Unlike Macron, an Elysee in the hands of Zemmour or Le Pen would likely mean less preoccupation with issues that the U.S. considers a priority such as a climate change. "They might not prioritize the large economic cost of keeping the Paris Climate Agreement alive and the potential to limit global warming to 1.5%,'' Dennison added.
MIGRATION IN THE CONTINENT
In light of a huge migrant influx into Europe last year, France's position on migration will continue to strongly impact countries on its periphery and beyond. This is especially so because of its geographical location as a leg on the journey of many migrants to the U.K.
A migrant vessel capsized in the English Channel last November killing 27 people, leading to a spat between France and the U.K. over who bore responsibility The British accused France of not patrolling the coast well enough, yet Macron said this was an impossible task. Observers consider France not to be particularly open to migrants within a European context and see Macron as a relative hardliner on migration.
But Le Pen or Zemmour would likely usher in tougher policies than Macron if they either emerge victoriously, such as slashing social allocations to non-French citizens and capping the number of asylum seekers. Some candidates have supported a Trump-style construction of border fences.
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