Mr. McFaul said his academic work had at times complicated his work as Mr. Obama’s Russia strategist, and he emphasized that he was in Russia to “execute and deepen and strengthen” the reset policy.

“There have always been rumors because I have written about certain subjects that that is what I am coming to do here,” he said. “That’s crazy. Just because you write about cancer doesn’t mean you advocate cancer. I’m a social scientist. I’ve written about democratization, but that’s my previous life.

“The most important thing for people to understand is that I’ve been a government official for three years,” he said. “Every step of the way, on every major issue to deal with this country, I’ve been intimately involved in the reset.”

It took almost no time for Mr. McFaul to slam into the forces awaiting him: the gimlet-eyed scrutiny accorded to American ambassadors in Moscow, the archaic codes of diplomatic life and the blasts of invective that issue from pro-Kremlin television. The occasion was a meeting Mr. McFaul attended on his second day of work, after devoting his first to talks with government officials.

A number of opposition figures arrived at the United States Embassy on that Tuesday to meet with a visiting American official, Deputy Secretary of State William J. Burns. Mr. Burns’s meetings had been arranged before Mr. McFaul’s arrival date was set, and the two men debated whether Mr. McFaul should attend, since protocol required him first to present his credentials to the Ministry of Foreign Affairs, Mr. McFaul said. He did so on Monday, and then attended the meetings, which are standard for high-level visits, he said.

That night, Channel 1 reported the meetings as “the first steps of the new U.S. ambassador to Russia.” A camera crew peppered the visitors with questions as they waited to be admitted to the embassy, and the clip was titled “Receiving Instructions at the United States Embassy.” An accompanying commentary singled out a book by Mr. McFaul, “Russia’s Unfinished Revolution” (Cornell University Press, 2001), and asked: “Is it possible that Mr. McFaul came to Russia to work in his specialty? That is, to finish the revolution?”

Over the weekend, two more broadcasts focused on the episode. A talk show host, Aleksei K. Pushkov, who is also chairman of the parliamentary foreign affairs committee, warned that Mr. McFaul might lose the ability to meet with high-level officials if he were seen as allying himself with the opposition. Russian leaders are acutely sensitive to any indication that the United States has taken a side in the coming elections, he said, though “there is no desire in Moscow to have a major crisis with the United States.”