“Any objective review of these claims should tell us what we already know — that the F.B.I. was right, that there was sufficient evidence to continue investigating certain Trump campaign officials for their connections to the Russian government, and that the Republicans are desperate to distract from that investigation,” said Representative Jerrold Nadler of New York, the top Democrat on the House Judiciary Committee.

Mr. Horowitz’s office is in the final stages of another high-profile investigation studying several contentious decisions made at the F.B.I. and Justice Department during the 2016 presidential campaign. Findings from one piece of that investigation prompted the firing this month of the former F.B.I. deputy director, Andrew G. McCabe. Mr. Horowitz is expected to release a broader report on his entire review in the coming weeks.

The decision punctuated a year of attacks by Mr. Trump on the Justice Department and the special counsel investigation. Mr. McCabe, who as a former top F.B.I. official is a potential witness in the inquiry, insisted he was fired in an effort to discredit any testimony he might give.

The debate over the surveillance of Mr. Page exploded into public view in January when Republicans on the House Intelligence Committee revealed that they had assembled a classified memo accusing law enforcement leaders of abusing their power to spy on Mr. Page.

The document’s chief claim was that the officials repeatedly used unsubstantiated Democratic-funded opposition research from Mr. Steele to obtain the surveillance warrant without adequately explaining to the judge the source of the information.

Mr. Trump declassified the memo over the objections of the F.B.I., which said it had “grave concerns” over its accuracy, a rare public break from the White House. Once it was released, Mr. Trump enthusiastically trumpeted it as evidence that the Russia investigation had been concocted to smear him politically.

Democrats on the committee countered with a memo of their own — one the president declined to declassify — offering a point-by-point refutation of the Republican document and blasting it as an intentionally misleading attempt to undermine the Russia investigation. They said law enforcement officials acted properly in seeking permission to spy on Mr. Page.