After months of trying to move the political needle in favour of Marine Le Pen in the French presidential election, American far-right activists on Saturday threw their weight behind a hacking attack against her rival, Emmanuel Macron, hoping to cast doubt on a pivotal election.

The efforts were the culmination of an extended campaign against Macron after his candidacy began to gain steam this year, with digital activists in the United States and elsewhere sharing tactics, tips and tricks across the English- and French-speaking parts of the Internet.

It is unclear whether the leaked documents, which some experts say may be connected to hackers linked to Russia, will affect the outcome of the election Sunday between Le Pen, the far-right candidate from the National Front, and Macron, an independent centrist. But the role of American far-right groups in promoting the breach online highlights their growing resolve to spread extremist messages beyond the United States.

The leak, which involved posting campaign documents like emails and accounting records to message boards, occurred late Friday, hours before a legal prohibition on campaign communications went into effect across France.

By Saturday, a trail of digital crumbs appeared to tie the attack on Macron’s campaign to Russian hackers. Forensics specialists found that one of the leaked Excel documents from Macron’s campaign had been modified on a Russian version of Excel, and edited on Russian-language computers.

Within hours after the hacked documents were made public, the hashtag #MacronLeaks began trending worldwide, aided by far-right activists in the United States who have been trying to sway the vote in favour of Le Pen.

Jack Posobiec, a journalist with the far-right news outlet the Rebel, was the first to use the hashtag with a link to the hacked documents online, which was then shared more widely by WikiLeaks.

While there is no evidence that the breach against Macron’s campaign was organized by this loosely connected group of far-right campaigners, the U.S. activists have been gathering on sites like 4chan and Discord, which were previously used to co-ordinate support for Donald Trump’s presidential campaign.

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