WASHINGTON — The Justice Department has conceded to a secretive intelligence court that the available evidence about Carter Page, a former Trump campaign adviser wiretapped by the F.B.I. during the Russia investigation, was legally insufficient to justify the last several months of his continued surveillance in 2017.
The department has also promised to sequester phone calls and emails it intercepted while intruding on Mr. Page’s privacy, according to a newly disclosed order by the court that oversees national-security wiretaps under the Foreign Intelligence Surveillance Act, or FISA.
The wiretapping of Mr. Page as part of the Russia investigation has been a political flash point. Last month, a scathing report by the department’s inspector general found that F.B.I. agents who assembled a description of the evidence that he might be a Russian agent had presented a misleading portrait of it for use in applications seeking the court’s permission to surveil him.
The FISA court approved an initial 90-day wiretap targeting Mr. Page in October 2016 and issued three renewal orders in 2017. But the department told the court that by those final two applications, “if not earlier, there was insufficient predication to establish probable cause to believe that Page was acting as an agent of a foreign power.”
The department informed the FISA court about its eventual loss of confidence in the available evidence about Mr. Page as part of a Dec. 9 letter to the court, following the release of the inspector general report. The existence of that letter had been known, but not this aspect of it.
Judge James E. Boasberg, the presiding judge on the FISA court, revealed that aspect in a two-page order to the department requiring that it provide more details about how it will protect Mr. Page’s information. The order was dated Jan. 7 but declassified and posted on the court website on Thursday.
Judge Boasberg’s order noted that the department appeared to be taking no position on whether the available evidence about Mr. Page was sufficient to meet the legal standard to wiretap him at the time of the initial order and of its first renewal, in January 2017.
The report by the office of the Justice Department’s independent inspector general, Michael E. Horowitz, found flaws in all four applications, showing a pattern of inaccurate statements and cherry-picking the evidence to highlight information that made Mr. Page look suspicious while omitting other facts that made him look less so.
But Mr. Horowitz’s report was particularly harsh about the renewal applications. His investigation showed that over time, the F.B.I. learned things that undermined the case that Mr. Page might be a Russian agent, but that agents charged with assembling the facts about him failed to pass the information on to colleagues, who in turn passed on the misleading portrait to the court.
For example, the applications included allegations about Mr. Page contained in a dossier compiled by Christopher Steele, a former British intelligence agent whose research was funded by Democrats. In January 2017, the F.B.I. interviewed Mr. Steele’s own primary source, and he contradicted what Mr. Steele had written in the dossier.
But rather than flagging the disconnect for the court — or deciding not to seek a renewal — the F.B.I. reported that its agents had met with the source to “further corroborate” the dossier and found him to be “truthful and cooperative,” leaving a misleading impression in renewal applications.
Mr. Horowitz also documented that the C.I.A. had told an F.B.I. agent that Mr. Page had spoken to the agency over the years about his contacts with Russian officials, which made that pattern look less suspicious. But the bureau did not pass that information on, and so the Justice Department cited that pattern as a reason to believe he might be a Russian agent.
As part of that criticism, Mr. Horowitz documented that during the preparation of the final renewal application, an F.B.I. lawyer altered an email from the C.I.A. in a way that made it look like the agency had said Mr. Page was “not a source,” contributing to the department’s continued failure to discuss Mr. Page’s relationship with the C.I.A. in the application.
Mr. Horowitz referred that lawyer, who has resigned from the bureau, for potential criminal investigation, and referred everyone else involved in the applications for potential internal discipline.