The FBI’s hostility toward Donald Trump during the Obama administration has come out in new testimony from Lisa Page, the former bureau lawyer who had an affair with investigative partner Peter Strzok.

It is known the two despised President Trump. They exchanged a series of text messages trashing Mr. Trump as an “idiot”, “awful” and a “loathsome human,” while praising Hillary Clinton. Agent Strzok, since fired, pledged to “stop” the candidate and confidently said he had an “insurance policy.”

Last July, Ms. Page underwent hours of closed testimony before a House joint Judiciary and Oversight committee task force. Parts of her transcript were published by the news site The Epoch Times.

Ms. Page disclosed that the FBI viewed Mr. Trump as a national security threat in relation to Russia. But if he lost the election, “there isn’t the same threat,” she said.

The context was this: two weeks after Mr. Strzok opened an investigation on July 31, 2016, into the Trump campaign on suspicion of colluding with Moscow, he messaged Ms. Page that, “there is no way he gets elected—but I’m afraid we can’t take that risk. It’s like an insurance policy in the unlikely event you die before you’re 40.”

Asked about his text by House investigators, Ms. Page responded by explaining they viewed Mr. Trump as a threat to the nation.

“What this text reflects is our sort of continuing check-in almost with respect to how quickly to operate, what types of tools to use, trying to be as quiet as possible about it because we knew so little about what—whether this was true or not true or what was going to come, because this is, as you said, so nascent in the investigation, and then ultimately trying to balance that against my view, in this case, which was we don’t need to go at a total breakneck speed because so long as he doesn’t become President, there isn’t the same threat to national security, right.”

She added, “Let’s be reasonable, let’s not, you know, throw the kitchen sink at this because he’s probably not going to be elected, and so then we don’t have quite as horrific a national security threat than if we do if he gets elected.”

Republicans believe the “insurance policy” remark referred to the investigation itself or to the anti-Trump Democratic Party-dossier.

Ms Page further explained the remark:

“He’s [Strzok‘s] making an analogy here so my suggestion is, let’s not, you know, throw the baby out with the bath water, let’s sort of be a little bit more cautious with respect to our investigative steps because if he’s not President, this plays a less of a threat to our national security.”

At this point in the campaign, there were two key developments: Mr. Trump had made it clear he wanted better relations with Russia President Vladimir Putin, praising the autocratic leader at times.

Secondly, the FBI knew the Russians were hacking Democratic Party computers. Wikileaks released the first batch of thousands of emails on July 22. The FBI determined they came via the Kremlin.

Today, more than 30 months after Mr. Strzok opened the probe, there is no public evidence of President Trump colluding with Moscow. No Trump associate has been charged with coordinating with Russia in its hacking and social media trolling meant to help the Republican and hurt Mrs. Clinton.

Special Counsel Robert Mueller informed Mr. Trump last year that he was not a target of his probe, meaning they don’t have evidence of a crime.

Republicans launched the House task force on the grounds that the Obama FBI and Justice Departments were determined to sabotage Mr. Trump during and after the election.

As an example, Republicans point to the Democratic Party-financed Christopher Steele dossier orchestrated by Fusion GPS, Mrs. Clinton’s opposition research agent.

Arriving in memo parts that summer, the FBI quickly embraced the anti-Trump charges from the ex-British spy who said he was determined to sink Mr. Trump. The FBI used the dossier as its main piece of evidence to gain a year’s worth of wiretaps on volunteer Carter Page. He has not been charged.

Mr. Strzok started the FBI probe based on a tip from an Australian diplomat that Trump volunteer George Papadopoulos in London had heard that Moscow might own thousands of Clinton emails.

There is no public evidence Mr. Papadopoulos acted on the tip. After a long investigation that included, he says, a wiretap and FBI informants inserted at his side, he was never charged with collusion. He spent less than two weeks in jail for lying to the FBI about when he joined the campaign.

Mr. Mueller kicked Ms. Page and Mr. Strzok off this team after viewing their text messages.

The Page transcripts appeared just as the New York Times reported on Friday that, after Mr. Trump fired FBI Director James Comey in May 2017, the FBI began an inquiry to see if Mr. Trump was a Moscow agent. The Times previously reported that Deputy Attorney General Rod Rosenstein, who appointed Mr. Mueller rather than keeping the Russia probe in-house, talked of wearing a wire when he met with the president.

To John Dowd, Mr. Trump’s former lawyer, it all adds up to FBI-Justice corruption.

“The NY Times story is an unwitting disclosure and verification of the utter corruption of their oaths by Comey and his colleagues to undermine the free election of the President of the United States,” Mr. Dowd told The Washington Times.

“It was apparently done under the supervision of the Deputy Attorney General who was reportedly ready to wear a wire to ensnare President Trump. This is the stuff of banana republics and dictatorships. This despicable, unlawful, official conduct undermines our entire federal criminal justice system which protects our liberty as a free people.”