Building a Eurasian economic bloc, including Ukraine, became a central goal for Mr. Putin upon his return to the presidency. His point man on the project was the economist Sergei Glazyev, an associate of Mr. Prokhanov’s and Mr. Dugin’s.

In an interview, Mr. Dugin was evasive when asked about his personal contact with Mr. Putin, saying only that he had been “in close contact with the Kremlin, and with those in the Kremlin who make decisions,” for the last 15 years. But he said the president, whom he described as a Henry Kissinger-style “pragmatist,” had embraced a version of his ideology because it served his interests domestically.

“It is popular, it is populist, it helps to explain all the processes which are going on in the country, and gradually — just by the logic of things, pragmatically, he becomes closer and closer to this ideology, just by the logic of events,” he said. He also offered a more human reason: that Mr. Putin had been stung by Western leaders’ apparent preference for his predecessor, Dmitri A. Medvedev, and then by the antigovernment protests that he believed were backed by the West.

Though a number of high-ranking officials around Mr. Putin have argued strenuously against this ideological shift, Mr. Dugin said that their influence had been waning steadily, and that the Crimean crisis left them no option but to “be quiet, or gather up their suitcases and leave Russia.”

“Anti-Americanism has become the main ideology, the main worldview among Russians,” he said. “Now, after Crimea, we have passed the point of no return. There will not be another Medvedev. There will never be another ‘reset,’ ever.”

Ideological mouthpieces have been used to send signals since the Soviet days — as a warning to adversaries or domestic dissenters — and it would be foolish to assume that Mr. Putin subscribes to their views. But there are important stakeholders who, faced with the threat of sanctions last week, have advocated that Russia cut itself off from the West. The most obvious among them is Vladimir I. Yakunin, president of Russian Railways and one of Mr. Putin’s trusted friends, who in a recent interview with The Financial Times described the struggle against a “global financial oligarchy” and the “global domination that is being carried out by the U.S.” On Tuesday, Mr. Yakunin presented plans for a Soviet-style megaproject to develop transportation and infrastructure in Siberia, a move toward “an economics of a spiritual type,” he said, that would insulate Russia from the West’s alien values.

He compared the project to monumental endeavors from the past: the adoption of Christianity in ancient Rus; the conquest of Siberia; electrification of the Soviet Union; the Soviet space program; and the Olympics in Sochi.