Last August, House investigators interviewed FBI deputy assistant director Jonathan Moffa about the Trump dossier, the collection of sensational allegations about Donald Trump and Russia compiled for Democrats during the 2016 campaign by the former British spy Christopher Steele. Republican lawyers had a simple question. Had the FBI confirmed any of the claims in the dossier?

Moffa's response set a new standard for non-answers.

"So, I like to talk about this in kind of a living sense," he began. "Though, because the idea is, you're never — you're constantly evaluating that reporting, you're constantly looking at incoming intelligence streams and investigative results. It's not a snapshot in time thing where you would look at reporting and say, it is — we have nothing to refute this today."

Moffa had more. "You have to constantly be sort of doing that," he continued. "And so, our analytic process in looking at this reporting and all reporting, really, is that more ongoing sense. So at the time, we are constantly re-evaluating, as time goes on, is the information here supported by facts we have elsewhere, or refuted by facts we have elsewhere?"

OK, said a frustrated Republican lawyer. What about the dossier? "I was just curious if you analyzed or verified every fact that was in these individual [dossier] reports as they're coming in."

"Got it," said Moffa. "So I have answered that. We, in an ongoing way, were looking at those facts, and doing that research and analytic work to try to verify, refute, or corroborate."

That's how it has gone for Republicans trying to find out whether the dossier's allegations have been corroborated. For more than two years, since the dossier was made public by BuzzFeed in January 2017, Republicans have asked the FBI what it has done to try to verify the dossier's key allegations. They've gotten nowhere, apparently because the FBI has never been able to verify the dossier's key allegations.

Those allegations were as specific as they were sensational. In no particular order, a few of the most important were:



The allegation that in 2013, in a Moscow hotel room, Trump watched as prostitutes performed a "golden showers" show on a bed in which former President Barack Obama had once slept, while Russian spy cameras recorded the whole thing.

The allegation that the head of Rosneft, the giant Russian state-owned oil company, offered low-level Trump foreign policy adviser Carter Page billions of dollars in return for ending U.S. sanctions against Russia.

The allegation that in August 2016 Trump fixer Michael Cohen met Russian officials in Prague to arrange secret payments to Russian hackers who attacked the Clinton campaign.

The allegation that short-term Trump campaign chairman Paul Manafort managed the "well-developed conspiracy of co-operation between [the campaign] and the Russian leadership," including "an intelligence exchange [that] had been running between them for at least eight years," and that Manafort was succeeded in that job by Cohen after Manafort left the campaign.

The FBI took the allegations very seriously. FBI Director James Comey briefed President-elect Trump on the Moscow hotel story in January 2017, a couple of weeks before the inauguration. The nation's intelligence chiefs also briefed the sitting president, Barack Obama. In addition, the FBI repeatedly presented information from the dossier to a secret court to receive a series of warrants to wiretap Page.

In public testimony after he was fired in May 2017, Comey famously called at least some of the dossier's allegations "salacious and unverified." More than a year later, in December 2018, House investigators asked Comey about the FBI's verification efforts. They didn't get much of an answer.

"Do you know whether the bureau endeavored to either contradict or corroborate factual assertions made in what has later been described as the Steele dossier?" asked then-Rep. Trey Gowdy.

"My understanding is that that effort — that an effort was under way to try to replicate, either rule in or rule out, as much of that collection of reports that's commonly now called the Steele dossier as possible," Comey answered, "and that work was ongoing when I was fired."

Comey did not say which of the dossier's allegations, if any, had been ruled in, and which, if any, had been ruled out.

There's no doubt the FBI tried to corroborate the dossier. And once such an effort began, people familiar with the bureau's ways say, the work would have been meticulous, with agents carefully trying to verify each line of the document.

But it's not clear how much the FBI had to work with. Moffa told investigators that the FBI relied a lot on media reports — "open source reporting," he called it — to evaluate the dossier. And when the FBI showed some lawmakers a table of sources used in the attempt to verify the dossier, "the majority of citations were to publicly available media reports," according to one lawmaker's assessment. One can imagine highly skilled FBI investigators, faced with the task of trying to prove the dossier accurate, frantically googling in an effort to find incriminating information.

In any event, not much, apparently, was found. A top FBI official said the corroboration effort was in its "infancy" when the bureau used the dossier for the first Page wiretap warrant in October 2016. Of course, by some accounts, some FBI officials did not know of the dossier until a month earlier, so it would not be surprising that full verification work had not been done.

A later FBI assessment said that Steele's reporting had been only "minimally corroborated." It's not clear what that meant. Comey told the House that the effort to corroborate the dossier "wasn't completed" by the time he left the FBI.

That was May 2017. In August 2017, the House Intelligence Committee subpoenaed information detailing the FBI's corroboration efforts. While the FBI did not turn over documents, bureau officials told congressional investigators in face-to-face meetings that they had not been able to verify the dossier's allegation of a Trump-Russia conspiracy.

In a December 2017 interview with the House, then-FBI acting director Andrew McCabe said the bureau worked hard to verify the dossier. But McCabe refused to say whether agents had been able to verify Steele's allegations, nor would he identify any substantive allegations that had been corroborated.

That takes the story to the beginning of 2018. After that, public information about verification efforts is slim. Of course, by that time the FBI had been trying for more than a year to corroborate the dossier with little or nothing to show for it.

But what if Trump-Russia special counsel Robert Mueller has corroborated the dossier's incendiary allegations? He seems to have explored every accusation of a Trump-Russia conspiracy, so it's possible he has found the proof that eluded earlier investigators. But if Mueller has found corroboration, he has not used it in the indictments of Manafort, Cohen, Rick Gates, Michael Flynn, George Papadopoulos, Roger Stone, and others. Given Mueller's penchant for so-called "speaking" indictments — indictments with detailed descriptions of events that go beyond what is legally necessary to present charges — it seems unlikely that there could be earth-shaking evidence that did not find its way into the indictments of key Trump-Russia players. But maybe Mueller has something. It is never safe to predict what the special counsel has, because no one outside his office knows what that is.

Despite the paucity of evidence, it is not unusual to hear the nation's most prestigious journalists and commentators claim that the dossier is accurate. They will say that the dossier has been proved "broadly" or "basically" or "largely" true. They will say that the dossier's main point is that Russia tried to interfere with the 2016 election, and that has proved accurate. Of course, Russia did try to interfere with the 2016 election, but that is not the dossier's main point. Its main point is that the Trump campaign and Russia conspired to interfere with the election.

That, of course, has not been proved, at least not yet. This July will mark three years since Steele first showed part of the dossier to the FBI. Since then, the dossier has roiled the Trump-Russia affair and been the subject of an intense research effort by those who, if they had confirmed damaging information, would use it against the president and his associates. So far, the long-sought corroboration just hasn't come.