When the nation’s intelligence chiefs go before Congress on Tuesday to provide their first public “Worldwide Threat Assessment” of President Trump’s second term, they’ll face an extraordinary choice.

Do they stick with their long-running conclusion about President Vladimir V. Putin of Russia, that his goal is to crush the Ukrainian government and “undermine the United States and the West?”

Or do they cast Mr. Putin in the terms Mr. Trump and his top negotiator with Russia are describing him with these days: as a trustworthy future business partner who simply wants to end a nasty war, get control of parts of Ukraine that are rightly his and resume a regular relationship with the United States?

The vexing choice has become all the more stark in recent days since Steve Witkoff, one of Mr. Trump’s oldest friends from the real estate world and his chosen envoy to the Mideast and Russia, has begun picking up many of Mr. Putin’s favorite talking points.

Mr. Witkoff wrote off European fears that Russia could violate whatever cease-fire is agreed upon and a peacekeeping force must be assembled to deter Moscow. In an interview with Tucker Carlson, the pro-MAGA podcaster, Mr. Witkoff said the peacekeeping idea was “a combination of a posture and a pose” by America’s closest NATO allies.

It is a view, he said, that was born of a “sort of notion of we’ve all got to be like Winston Churchill, the Russians are going to march across Europe.” He continued: “I think that’s preposterous.”

Just over three years after Russian troops poured into Kyiv and tried to take out the government, Mr. Witkoff argued that Mr. Putin doesn’t really want to take over all of Ukraine.

“Why would they want to absorb Ukraine?” he asked Mr. Carlson. “For what purpose, exactly? They don’t need to absorb Ukraine.” All Russia seeks, he argues, is “stability there.”

“I thought he was straight up with me,” Mr. Witkoff said of Mr. Putin, a striking characterization of a longtime U.S. adversary, and master of deception, who repeatedly told the world he had no intention of invading Ukraine.

Of all the head-spinning reversals in Washington these days, perhaps it is the Trump administration’s view of Russia and its seeming willingness to believe Mr. Putin that leave allies, intelligence officials and diplomats most disoriented.

Until Mr. Trump took office, it was the consensus view of the United States and its allies that they had been hopelessly naïve about Russia’s true ambitions for far too long — that they had failed to listen carefully to Mr. Putin when he first argued, in 2007, that there were parts of Russia that needed to be restored to the motherland. Then he invaded Georgia, annexed Crimea and sent the military — out of uniform — to conduct a guerrilla war in the Donbas.

Still, sanctions were slow to be applied, and Europe was far too slow to rearm — a point Mr. Trump himself makes when he presses the Europeans for more funds to defend themselves.

Now, Mr. Trump refuses to acknowledge the obvious, that Russia invaded Ukraine. He has been openly contradicted by several European leaders, who say that even if the United States plans to seek a normalization of relations with Russia, they do not. “I don’t trust Putin,” the British prime minister, Keir Starmer, told The New York Times last week. “I’m sure Putin would try to insist that Ukraine should be defenseless after a deal because that gives him what he wants, which is the opportunity to go in again.”

But for the American intelligence agencies, whose views are supposed to be rooted in a rigorous analysis of covertly collected and open-source analysis, there is no indication so far that any of their views about Mr. Putin and his ambitions have changed. So it will be up to the new director of national intelligence, Tulsi Gabbard, and the new C.I.A. director, John Ratcliffe, to walk the fine line of describing Russia as a current adversary and future partner.

Mr. Witkoff headed down that road in his conversation with Mr. Carlson. “Share sea lanes, maybe send LNG gas into Europe together, maybe collaborate on A.I. together,” he said, after imagining a negotiated cease-fire in which Russia gets to hold the lands it now occupies and gets assurances that Ukraine will never join NATO. “Who doesn’t want to see a world like that?”

Senator Mark Warner of Virginia, the ranking Democrat on the chamber’s Intelligence Committee, said comments by Mr. Witkoff and others in the Trump administration are deeply disorienting to American spies.

“If you grew up in the intelligence community knowing all the awful things Vladimir Putin had done and all of a sudden you have a change in posture where you completely take Russia’s side, how do you make sense of that?” Mr. Warner said.

Mr. Warner said the document that the intelligence community will unveil on Tuesday, its annual threat assessment, is very traditional and in keeping with previous versions of it. But what Mr. Trump’s intelligence leaders will say in testimony is not as clear. So far, Mr. Warner said, the administration’s comments on Ukraine have reflected anything but the traditional view of the threat from Russia.

The shifting American policy on Russia, Mr. Warner said, threatens intelligence partnerships. While America collects far more intelligence than other countries, he said, the combined contributions of key allies are substantial. And if their concerns about American policy and its faithful analysis of intelligence grow, they will share less.

Officials of several allies, while declining to speak on the record, pointed to several of Mr. Witkoff’s statements with alarm, saying they closely reflected Russian talking points. He endorsed Russian “referendums” in four key Ukrainian provinces that were widely viewed as rigged, with voters threatened with torture and deportation if they cast their ballot the wrong way. But Mr. Witkoff spoke as if they were legitimate elections.

“There have been referendums where the overwhelming majority of the people have indicated that they want to be under Russian rule,” he said. Shortly afterward, Oleksandr Merezhko, the chairman of the Foreign Affairs Committee in the Ukrainian Parliament, said on Monday that Mr. Witkoff should be removed from his position.

“These are simply disgraceful, shocking statements,” Mr. Merezhko told Ukrainian media. “He is relaying Russian propaganda. And I have a question: Who is he? Is he Trump’s envoy, or maybe he’s Putin’s envoy?”

President Volodymyr Zelensky of Ukraine was more circumspect in an interview with Time magazine released on Monday. He said he believed “Russia has managed to influence some people on the White House team through information.” Earlier, he had talked about the “web of disinformation” surrounding Mr. Trump, saying it contributed to their famously poor relationship.

He noted that Mr. Trump had repeated Mr. Putin’s claim that retreating Ukrainian forces in western Russia had been encircled.

“That was a lie,” Mr. Zelensky said.

Constant Méheut contributed reporting from Kyiv.