Updated

As French voters cast ballots for president Sunday, they're making a choice that will resonate far beyond France's borders, from Syrian battlefields to Hong Kong trading floors and the halls of the U.N. Security Council.

The future of Europe is at stake as this country faces an election unlike any other, one that may reshape France's post-war identity and indicate whether global populism is ascendant or on the decline.

Here are a few reasons why the French election, taking place in two rounds starting Sunday, matters:

RISK OF A FREXIT

Most of the 11 candidates are campaigning against the European Union, blamed for myriad woes. Two with a chance at the presidency, far-right Marine Le Pen and far-left Jean-Luc Melenchon, could seek to pull France out of the union and its shared euro currency altogether.

A French exit of either would be far worse than Britain's — it could spell death for the EU, the euro and the whole idea of European unity borne from the blood of World War II. France is a founding member of the EU, and its main driver along with former rival Germany.

Financial markets are already jittery over a possible Frexit, fearing controls on money transfers, capital flight, a plague of defaults and lawsuits on bonds and contracts. Le Pen's team downplays apocalyptic scenarios, arguing that the euro is headed for a breakup eventually anyway.

Le Pen and Melenchon also blame free trade pacts for killing French jobs and want to renegotiate them, which would cause a financial tangle for the rest of the EU and France's trade partners.

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TRUMP AND POPULISM

If Le Pen or Melenchon reach the second round, it will be seen as a clear victory for the populist wave reflected by the votes for Donald Trump and Brexit. Many French workers who have lost out because of globalization are similarly fed up with establishment parties and especially attracted by promises of ditching the status quo.

Alternatively, if neither candidate makes it past Sunday's first round into the May 7 runoff, that's a clear message that populist nationalism is receding.

Centrist Emmanuel Macron and conservative Francois Fillon are committed to European unity and would reform labor rules but not make any drastic moves. Macron has framed himself as a bulwark against Trump's protectionism.

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ASSAD'S SYRIA AND PUTIN'S RUSSIA

A nuclear power with a seat on the U.N. Security Council and tens of thousands of troops around the world, France is a key U.S. ally in the campaign against the Islamic State group and major diplomatic player.

Macron would likely keep up the French operations against extremists in Iraq and Syria and Africa's Sahel region — and keep up pressure on Russia over Ukraine and its actions to bolster Syrian President Bashar Assad.

The other three front-runners, on the other hand, had supported restoring dialogue with Assad to find a political solution for Syria. Le Pen firmly backs Assad and distanced herself from Trump over recent U.S. airstrikes targeting Assad's regime.

Le Pen also met recently with President Vladimir Putin and would push for lifting sanctions against Russia over the conflict in Ukraine.

Fillon too has been friendly with Putin in the past, but has taken a harder stance lately — notably since chemical weapon attack blamed on Assad's forces.