It wasn't the dossier, fellas

During a night of heavy drinking at an upscale London bar in May 2016, George Papadopoulos, a young foreign policy adviser to the Trump campaign, made a startling revelation to Australia’s top diplomat in Britain: Russia had political dirt on Hillary Clinton.

About three weeks earlier, Mr. Papadopoulos had been told that Moscow had thousands of emails that would embarrass Mrs. Clinton, apparently stolen in an effort to try to damage her campaign.

Exactly how much Mr. Papadopoulos said that night at the Kensington Wine Rooms with the Australian, Alexander Downer, is unclear. But two months later, when leaked Democratic emails began appearing online, Australian officials passed the information about Mr. Papadopoulos to their American counterparts, according to four current and former American and foreign officials with direct knowledge of the Australians’ role.

The hacking and the revelation that a member of the Trump campaign may have had inside information about it were driving factors that led the F.B.I. to open an investigation in July 2016 into Russia’s attempts to disrupt the election and whether any of President Trump’s associates conspired.

If Mr. Papadopoulos, who pleaded guilty to lying to the F.B.I. and is now a cooperating witness, was the improbable match that set off a blaze that has consumed the first year of the Trump administration, his saga is also a tale of the Trump campaign in miniature. He was brash, boastful and underqualified, yet he exceeded expectations. And, like the campaign itself, he proved to be a tantalizing target for a Russian influence operation.

While some of Mr. Trump’s advisers have derided him an insignificant campaign volunteer or a “coffee boy,” interviews and new documents show that he stayed influential throughout the campaign. Two months before the election, for instance, he helped arrange a New York meeting between Mr. Trump and President Abdel Fattah el-Sisi of Egypt.

The information that Mr. Papadopoulos gave to the Australians answers one of the lingering mysteries of the past year: What so alarmed American officials to provoke the F.B.I. to open a counterintelligence investigation into the Trump campaign months before the presidential election?

It was not, as Mr. Trump and other politicians have alleged, a dossier compiled by a former British spy hired by a rival campaign. Instead, it was firsthand information from one of America’s closest intelligence allies.

Interviews and previously undisclosed documents show that Mr. Papadopoulos played a critical role in this drama and reveal a Russian operation that was more aggressive and widespread than previously known. They add to an emerging portrait, gradually filled in over the past year in revelations by federal investigators, journalists and lawmakers, of Russians with government contacts trying to establish secret channels at various levels of the Trump campaign.

The F.B.I. investigation, which was taken over seven months ago by the special counsel, Robert S. Mueller III, has cast a shadow over Mr. Trump’s first year in office — even as he and his aides repeatedly played down the Russian efforts and falsely denied campaign contacts with Russians.

They have also insisted that Mr. Papadopoulos was a low-level figure. But spies frequently target peripheral players as a way to gain insight and leverage.

F.B.I. officials disagreed in 2016 about how aggressively and publicly to pursue the Russia inquiry before the election. But there was little debate about what seemed to be afoot. John O. Brennan, who retired this year after four years as C.I.A. director, told Congress in May that he had been concerned about multiple contacts between Russian officials and Trump advisers.

Russia, he said, had tried to “suborn” members of the Trump campaign.

Britain’s spy agencies played a crucial role in alerting their counterparts in Washington to contacts between members of Donald Trump’s campaign team and Russian intelligence operatives, the Guardian has been told.

GCHQ first became aware in late 2015 of suspicious “interactions” between figures connected to Trump and known or suspected Russian agents, a source close to UK intelligence said. This intelligence was passed to the US as part of a routine exchange of information, they added.

Over the next six months, until summer 2016, a number of western agencies shared further information on contacts between Trump’s inner circle and Russians, sources said.

The European countries that passed on electronic intelligence – known as sigint – included Germany, Estonia and Poland. Australia, a member of the “Five Eyes” spying alliance that also includes the US, UK, Canada and New Zealand, also relayed material, one source said.

Another source suggested the Dutch and the French spy agency, the General Directorate for External Security or DGSE, were contributors.

It is understood that GCHQ was at no point carrying out a targeted operation against Trump or his team or proactively seeking information. The alleged conversations were picked up by chance as part of routine surveillance of Russian intelligence assets. Over several months, different agencies targeting the same people began to see a pattern of connections that were flagged to intelligence officials in the US.