Mr. Horowitz found no evidence that political bias — as opposed to gross incompetence or confirmation bias — was behind the bungling. But he rejected as unsatisfactory the explanation that the agents were busy on other aspects of the Russia investigation.

The F.B.I. filing last week described 12 steps the bureau is taking to make sure that any potentially relevant and mitigating information reaches the court in future applications, like enhancing training and expanding verification forms and checklists that agents must fill out.

Mr. Kris also made a series of smaller suggestions to improve those ideas, like imposing a deadline for the F.B.I. to carry out one of its proposed changes, which the bureau had not included in its filing, and ordering it to provide regular updates on its progress.

Mr. Kris has written extensively about FISA, a notoriously complex law, and he led the Justice Department’s National Security Division in the first term of the Obama administration. He was appointed to help the court analyze the F.B.I.’s proposal by Judge James E. Boasberg, an Obama appointee selected by Chief Justice John G. Roberts Jr. of the Supreme Court to serve as the FISA court’s presiding judge starting this year.

President Trump criticized the selection of Mr. Kris over the weekend in a dispute that traces back to a 2018 memo attacking the Page FISA applications by Representative Devin Nunes, Republican of California and a staunch Trump ally. He was then the chairman of the House Intelligence Committee.

Mr. Kris criticized Mr. Nunes’s memo at the time as “dishonest” and “disgraceful and dangerous nonsense.” But Mr. Nunes’s allies have portrayed Mr. Horowitz’s findings as vindicating him, and on Jan. 12, Mr. Nunes told Fox News that Mr. Kris had a history of “defending dirty cops” and labeled his appointment “another misstep,” calling for the FISA court to be abolished.

Mr. Trump echoed the attack in a Twitter post, writing: “You can’t make this up! David Kris, a highly controversial former DOJ official, was just appointed by the FISA Court to oversee reforms to the FBI’s surveillance procedures. Zero credibility. THE SWAMP!”