The House’s top investigator on Sunday said the FBI failed to notify a surveillance court that it was relying on material backed by the Democratic National Committee and the Hillary Clinton campaign when it asked to snoop on a former adviser to the Trump campaign.

Rep. Trey Gowdy, South Carolina Republican, also said judges wouldn’t have authorized and repeatedly renewed a warrant to spy on the former campaign aide, Carter Page, if it hadn’t been for the material in that very dossier, compiled by former British spy Christopher Steele.

The revelations shouldn’t upend investigations into Russian meddling in the 2016 election, the congressman said, but he thinks the FBI erred by failing to disclose their sources’ anti-Trump agenda in a footnote on their evidence.

“They could have easily said it was the DNC and Hillary Clinton. That would have been really easy,” Mr. Gowdy told CBS’s “Face the Nation.” “It took longer to explain it the way they did than if they just came right out and said, ‘Hillary Clinton for America and DNC paid for it.’ But they didn’t do that.”

Mr. Gowdy was involved in drafting a bombshell memo that details the FBI’s decision to use the Clinton-backed material to try to spy on Mr. Page in October 2016. It also explores the role of top FBI and Justice Department officials in seeking and renewing those snooping powers.

President Trump said the memo “totally vindicates” him as he is dogged by claims that his 2016 campaign colluded with Russia.

House Speaker Paul D. Ryan, Wisconsin Republican, and Mr. Gowdy say that wasn’t the point of the memo. Yet it has kicked up a political firestorm, with Democrats chastising its lead author — Rep. Devin Nunes, California Republican and chairman of the House Permanent Select Committee on Intelligence — for pulling back the curtain on the secretive U.S. Foreign Intelligence Surveillance Court and its sensitive processes.

They say the four-page memo amounts to an incomplete “hit job” designed to sow doubt about investigations into the Trump campaign’s interactions with Russians.

Senate Minority Leader Charles E. Schumer, New York Democrat, told Mr. Trump on Sunday to support the release of a paper by Rep. Adam B. Schiff of California that serves as a Democratic rebuttal to Mr. Nunes’ memo, which was released Friday with White House approval.

Republicans on the House intelligence committee voted to reject Mr. Schiff’s memo, even as they green-lighted their own.

“I believe it is a matter of fundamental fairness that the American people be allowed to see both sides of the argument and make their own judgments,” Mr. Schumer said.

He said the Schiff memo sheds new light on why the FBI felt it needed to watch Mr. Page and his interactions with Russians.

Mr. Gowdy said Democrats are the ones being one-sided.

“I get that Adam Schiff and others are worried about what’s not in my memo. I wish that they were equally concerned about what’s not in the FISA application, which is a lot of really important information about the source, and its subsources, and the fact that he was hired by the DNC and the Clinton campaign, and the fact that he was biased against President Trump,” said Mr. Gowdy, who last week said he will return to the legal field instead of seeking re-election.

“I would argue it’s also somewhat unprecedented to rely on political opposition research to instruct and inform an application. And it’s really bad precedent and unprecedented to not tell a court that a source has this level of bias,” he said.

Mr. Gowdy said he hopes the revealing memo is a “one-off,” but he also thinks it’s important to detail how the FBI sought its snooping powers because FISA judges don’t perform independent research.

He is among the top Republicans preaching caution, even as Mr. Trump’s conservative allies say heads should roll at the FBI and Justice Department.

After the memo was released Friday, Mr. Trump told reporters that the FBI’s conduct was a disgrace. He refused to say whether he had confidence in Deputy Attorney General Rod Rosenstein, who signed at least one of the surveillance applications and later appointed Robert Mueller as special counsel to investigate the Russia accusations.

Senate Democrats say any move to upend the Russia investigations would cross a red line akin the 1973 “Saturday Night Massacre,” in which President Nixon’s attorney general and his deputy opted to resign rather than carry out the president’s order to fire Watergate prosecutor Archibald Cox.

“To say that that’s the end of the investigation, that this is all that Donald Trump needs to fire Rosenstein or to fire Bob Mueller, I’ll just tell you, this could precipitate a constitutional crisis,” Senate Minority Whip Richard J. Durbin, Illinois Democrat, told CNN’s “State of the Union.”

The New York Times recently reported that Mr. Trump ordered Mr. Mueller’s firing in June, only to back off when the White House counsel threatened to resign.

Former White House Chief of Staff Reince Priebus, who was ousted in July, said he never got the sense that Mr. Trump wanted to or tried to get rid of Mr. Mueller.

“I never heard the idea or the concept that this person needed to be fired. I never felt that it was relayed to me that way either,” Mr. Priebus told NBC’s “Meet the Press.” “And I would know the difference between a level-10 situation, as reported in that story, and what was reality. And it just, to me, it wasn’t reality.”

Mr. Gowdy took pains to divorce his work on the Nunes memo from the Mueller investigation, which he said goes far beyond the Steele dossier.

“There is a Russia investigation without a dossier,” he said, rattling off a list of other events, such as a mysterious meeting between a Russian lawyer and Trump officials at Trump Tower.

The Republican memo says the FBI dug into the Trump campaign after another one of its aides, George Papadopoulos, reportedly boasted in mid-2016 that Russia had dirt on Mrs. Clinton.

Furthermore, Mr. Gowdy said the Republican memo “doesn’t have anything to do with obstruction of justice,” something Mr. Mueller is reportedly exploring after Mr. Trump fired FBI Director James B. Comey last year.

Democrats have warned Mr. Trump not to use the memo to terminate Mr. Rosenstein, too, saying it would cross a red line.

Richard Painter, the chief ethics attorney for President George W. Bush, said the public outcry over Mr. Rosenstein’s firing might be enough to stop the president from pulling the trigger.

“If he wants to fire Rosenstein, it will get ugly,” Mr. Painter said. “He’ll just dig himself into a bigger hole with obstruction accusations because it will seem like he’s firing Rosenstein to get at Mueller. The advice I would give him is to leave it alone. If the president just stops, that could minimize his exposure to possible obstruction of justice.”

The Nunes memo largely focuses on Mr. Steele’s role and conflicts of interest that pointed to a pattern of bias against Mr. Trump.

Mr. Steele said he obtained information about Mr. Trump from unidentified officials at the Kremlin in Moscow. His dossier was eventually given to Fusion GPS, a liberal research firm funded by the Clinton campaign and DNC.

Then-deputy FBI Director Andrew McCabe told the House intelligence committee in December that a surveillance warrant for Mr. Page would not have been sought without the information from Mr. Steele.

Mr. McCabe retired earlier than expected on Jan. 29, one day after FBI Director Christopher Wray saw the memo.

The document also details a partisan conflict of then-Associate Deputy Attorney General Bruce Ohr, who was in contact with Mr. Steele while Mr. Ohr’s wife was employed by Fusion GPS “to assist in the cultivation of opposition research on Trump” for Mrs. Clinton.

“Ohr later provided the FBI with all of his wife’s opposition research, paid for by the DNC and Clinton campaign via Fusion GPS,” the memo stated. “The Ohrs’ relationship with Steele and Fusion GPS was inexplicably concealed from the [court].”

In September 2016, Mr. Steele acknowledged to Mr. Ohr his dislike for then-candidate Trump, saying he was “desperate that Donald Trump not get elected and was passionate about him not being president,” the memo said.

“This clear evidence of Steele’s bias was recorded by Ohr at the time and subsequently in official FBI files but not reflected in any of the Page FISA applications,” the Nunes memo said.

Mr. Ohr was demoted at Justice late last year.

⦁ Dan Boylan and Jeff Mordock contributed to this report.

Sign up for Daily Newsletters Manage Newsletters

Copyright © 2020 The Washington Times, LLC. Click here for reprint permission.