WASHINGTON — An inspector general uncovered pervasive problems in the F.B.I.’s preparation of wiretap applications, according to a memo released Tuesday about an audit that grew out of a damning report last year about errors and omissions in applications to target a former Trump campaign adviser during the Russia investigation.
The follow-up audit of unrelated cases by the Justice Department’s independent watchdog, Michael E. Horowitz, revealed a broader pattern of sloppiness by the F.B.I. in seeking permission to use powerful tools to eavesdrop on American soil in national security cases. It comes at a time when Congress is debating new limits on the Foreign Intelligence Surveillance Act, or FISA.
The finding of systemic incompetence is devastating for the F.B.I. But in the Trump era, the discovery is leavened by an unusual side benefit for the bureau: It undercuts the narrative fostered by President Trump and his supporters that the botching of applications to surveil his campaign adviser Carter Page is evidence that the F.B.I. engaged in a politically biased conspiracy.
Mr. Horowitz’s investigators reviewed so-called Woods files, where the F.B.I. is supposed to catalog supporting documentation for factual claims in a FISA application, in a random sample of 29 requests to wiretap someone as part of a terrorism or espionage investigation under FISA. They found problems with all 29.
“We do not have confidence that the F.B.I. has executed its Woods Procedures in compliance with F.B.I. policy, or that the process is working as it was intended to help achieve the ‘scrupulously accurate’ standard for FISA applications,” the inspector general report said.
Testing the FISA applications against their underlying evidence “identified apparent errors or inadequately supported facts in all of the 25 applications we reviewed,” the report said.
The other four could not be scrutinized at all because the F.B.I. could not even locate the required Woods file. In the 25 applications reviewed, there was an average of about 20 problems each. One alone had 65 issues.
In a statement appended to the report, the F.B.I. said that it accepted the findings but also that it believed it was already addressing the source of the problems through corrective steps it put in place after the earlier report about Mr. Page. Among those steps are greater training and new checklists that officials preparing documents for FISA applications must follow.
Some of the problems the review found matched issues the inspector general previously uncovered with the Page applications. For example, F.B.I. policy requires that when investigators submit to a court a factual assertion by a confidential source they must internally document that the source’s handler was consulted about those facts and the source’s credibility and background.
The Page applications had relied in part on information provided by Christopher Steele, a former British intelligence agent who compiled a dossier of claims about purported Trump-Russia links. The inspector general previously found that the applications overstated the value of Mr. Steele’s prior assistance — representations his handling agent had not approved.
The follow-up audit released on Tuesday found a pattern: About half of the applications contained information from confidential sources, and “many of them” lacked the required documentation of any check-in with their handling agents.
Another problem the inspector general uncovered with the Page applications was that when the F.B.I. sought renewed permission from the court to continue wiretapping him, it failed to reverify facts repeated from earlier applications.
For example, after the first renewal of the Page surveillance, the F.B.I. talked to a person Mr. Steele had relied upon and who expressed disagreement with how the dossier portrayed his information. But law enforcement officials continued to cite that information in the second and third renewal applications without noting the source’s objections, which most likely would have given the judge reason to view it with greater skepticism.
A failure to consistently reverify recycled statements of fact during renewals also appears to be common, the new report said.
In one case, F.B.I. agents even repeated errors in applications submitted for wiretap renewals. In others, they only corroborated new facts, not earlier assertions they had verified when originally seeking the wiretaps and were relying on again.
“This practice directly contradicts F.B.I. policy,” the report said.
The F.B.I.’s systematic sloppiness in preparing FISA applications could be even worse than the new audit indicates because Mr. Horowitz’s office did not look through the voluminous raw case files in search of any mitigating facts the applications had omitted, which was among the problems his office’s closer scrutiny of the Page applications identified.
The system is inherently vulnerable to the risk that lower-level agents will cherry-pick evidence when compiling factual summaries, leaving out evidence that weakens their case when they seek permission to conduct surveillance either deliberately or through confirmation bias, current and former national security officials have said.
Audits to catch omissions are particularly difficult because they require the time and resources to achieve a deep-dive understanding of extensive investigative files, like the inspector general’s office spent over a year doing with the Russia case and Mr. Page.
As part of its changes since the Page report, the F.B.I. has created new checklists to remind agents to consider whether there is any mitigating evidence. The FISA court has ordered officials to swear in future cases that applications to the court contain “all information that might reasonably call into question the accuracy of the information or the reasonableness of any F.B.I. assessment in the application, or otherwise raise doubts about the requested findings.”
The new report took no position on the scale of the errors in the application materials — whether they were minor or could have changed law enforcement officials’ decisions to seek wiretap orders or a judge’s decision to approve them.
The F.B.I. and the Justice Department’s National Security Division also occasionally audit FISA applications for accuracy. The inspector general report said it examined 34 such accuracy review reports covering 42 FISA applications at eight field offices between 2014 and 2019.
Those reviews found a total of 390 issues in 39 of the 42 applications, “including unverified, inaccurate, or inadequately supported facts, as well as typographical errors,” it said.
The findings of systemic problems with its work seeking FISA applications comes at a delicate time for the F.B.I., which has expressed chagrin at the errors and omissions in the Page applications while promoting the importance of preserving its ability to use national security wiretaps when investigating suspected spies and terrorists.
In March, the House passed new curbs on FISA as part of a bill to extend three F.B.I. tools for national security investigations that expired on March 15. For example, the bill would push the FISA court to appoint an outsider to critique the government’s arguments when a wiretap application raises serious issues about First Amendment activity, which could include political campaigns.
Some libertarian-leaning senators of both parties have argued that the House bill falls short and that more new restrictions are necessary. One of them, Senator Ron Wyden, Democrat of Oregon, said on Tuesday that the new findings underscored the need for greater safeguards.
“The inspector general’s findings of widespread abuses indicate that Carter Page was not singled out,” Mr. Wyden said. “Congress should write reforms into black-letter law to ensure that every American’s rights are protected, not just friends of the president.”
Marc Raimondi, a spokesman for the Justice Department’s national security division, pointed to the changes the department and the F.B.I. have already made. He also noted that Attorney General William P. Barr has further required the bureau to get higher-level approval to open politically sensitive investigations and supports changes in the House’s bill.
“The department is committed to putting the inspector general’s recommendations into practice and to implementing reforms that will ensure that all FISA applications are complete and accurate,” Mr. Raimondi said.
