The office is one of many things about Page that are less than initially meets the eye. When Trump announced Page as one of his foreign-policy advisers during a meeting with The Washington Post editorial board in March 2016, he was eager to tout Page’s credentials, identifying him as “Carter Page, Ph.D.” Page’s doctoral adviser for his degree, received in 2011 from the University of London’s School of Oriental and African Studies, was Shirin Akiner, a controversial scholar who has been derided by fellow academics and human rights groups for trying to whitewash human rights abuses in Uzbekistan. But in an email, Akiner told me, “I am afraid I have no information about Carter Page — some 10 years ago, he was one of my many students.”

Page tried unsuccessfully to publish his doctoral dissertation, on energy in Central Asia and Russia, as a book — a failure for which he has blamed the “anti-former Soviet Union, anti-Russia sentiment of various academic publishers.” But one political scientist who reviewed Page’s manuscript told me: “It was very analytically confused, just throwing a lot of stuff out there without any real kind of argument. I gave it a thumbs down — and that’s kind of rare in this business for a review of a full book manuscript.”

Before founding Global Energy Capital in 2008, Page spent seven years working for Merrill Lynch in London, Moscow and New York and, according to his corporate biography, was “involved in over $25 billion of transactions in the energy-and-power sector.” But his involvement appears to have been peripheral at best. In Moscow, he was nicknamed Stranichkin, from the Russian word stranichka, meaning “little page.” “He wasn’t great, and he wasn’t terrible,” Sergei Aleksashenko, who ran Merrill Lynch’s Moscow office while Page worked there, told the journalist Julia Ioffe. “What can you say about a person who in no way [is] exceptional?”

As a midshipman at the Naval Academy, Page read and was profoundly affected by “The Wise Men,” Walter Isaacson and Evan Thomas’s book about Dean Acheson, Averell Harriman and the other mandarins who shaped Cold War-era foreign policy. He set out to play a similarly influential, “discreetly backstage” role in world affairs. People who encountered Page in his pre-Trump days recall him as someone who was forever struggling in that effort. Stephen Sestanovich, a professor at Columbia University’s School of International and Public Affairs, remembers running into Page — who is a prodigious conference-goer — on the sidelines of various Council on Foreign Relations forums and round tables related to Russia. “His view of how the world worked seemed to have an edgy Putinist resentment to it,” Sestanovich says. “I think Carter genuinely felt an affinity for Putin’s critique of the U.S. foreign-policy establishment and its unfairness to Russia, because he wasn’t doing any better with that establishment than Putin was.” In 2013, a Russian intelligence operative who was posing as a United Nations diplomat met Page at an Asia Society conference; according to the F.B.I., the Russian spy tried to recruit Page but encountered difficulties because, as he was heard telling a colleague in an F.B.I. wiretap, Page was “an idiot.”

It was the Trump campaign that finally provided Page what he had been seeking for years: a seat at the table. Ed Cox, the chairman of the New York State Republican Committee and an acquaintance, secured Page a meeting in early 2016 with Trump’s campaign manager, Corey Lewandowski, who in turn passed off Page to Sam Clovis, a talk-show host and conservative activist in Iowa who was building out Trump’s foreign-policy team. Even among Trump advisers, that team was an object of derision. “To call them D-listers would be an insult to D-listers,” one former Trump adviser says. But Page didn’t see it that way at all. “These were some of the best discussions I ever had, with some of the most impressive people,” he recalls. “It was like an oasis.”

Page’s time at the oasis would be brief. That July, he traveled to Moscow for five days to give a speech at the New Economic School. Not long after he returned, he received a text message from a Wall Street Journal reporter asking whether he met in Moscow with Igor Sechin, a Putin ally who is now chief executive of the Russian oil conglomerate Rosneft, and Igor Diveykin, a top Russian intelligence official. Similar questions from other reporters soon followed. Page told them — and still maintains — that he didn’t meet either man. But in late September, Yahoo News ran an article reporting that American intelligence officials suspected that Page had met with both of them in Moscow — a claim, Page later discovered, that appeared in the dossier on Trump’s suspected Russia entanglements complied by the former British intelligence agent Christopher Steele. Three days after the Yahoo report, Page announced he was taking a “leave of absence” as a campaign adviser.