The case President Trump and his allies have built against the Justice Department and the FBI is circumstantial at best.

And on Thursday, the various arguments Trump and his Republican allies have leaned on to suggest or outright claim FBI bias against the president got knocked down, one by one, by the top of the bureau's chain of command.

What's more, Deputy Attorney General Rod J. Rosenstein and FBI Director Christopher A. Wray categorically denied these characterizations of the FBI's work while under oath. Wray and Rosenstein, who appointed special counsel Robert S. Mueller III, testified Thursday for hours to the House's Judiciary Committee.

Let's run down the top GOP attacks thrown at the Russia investigation and what Rosenstein and Wray had to say about them.

1. GOP argument: The Russia investigation is led by Democrats

Some members of Mueller's team have donated to Democrats. But not all, as Trump frequently frames it.

And at least one of those same Mueller staffers also donated to Republicans. In addition, as Wray and Rosenstein underscored Thursday after questioning from Rep. Luis V. Gutiérrez (D-Ill.), they aren't Democrats.

“I do not consider myself an angry Democrat,” Wray said.

“Are you a Democrat?” Gutiérrez asked Wray. “No I am not,” he replied.

Gutiérrez: “Mr. Rosenstein, are you a Democrat?”

Rosenstein: “I am not a Democrat, and I am not angry.”

What's more, Rosenstein said he wasn't aware of any conflicts of interest Mueller himself might have, which Trump cryptically referred to in a tweet Thursday morning.

2. GOP argument: Rosenstein inappropriately approved spying on the Trump campaign

House Republicans declassified a memo this February arguing that the FBI leaned on politically biased information to get a warrant to spy on a former Trump campaign official, Carter Page. In that memo, Rosenstein was mentioned — right as it was reported that Trump was considering using the memo to fire Rosenstein.

Legal experts have said Rosenstein played by the book on authorizing a warrant renewal to spy on Page, which is known as a FISA warrant. Plus, he wasn't a big part of it. The original decision to spy on Page happened before Rosenstein was in the job. And he's not the one who approved subsequent spying; only federal judges on a secret court can do that.

Rosenstein underscored all of that Thursday: “It'd be a dereliction of duty for me to fail to approve a FISA that was justified by the facts and the law,” Rosenstein said.

3. GOP argument: The Justice Department is hiding something when it doesn't immediately hand over documents to Congress

Rosenstein and House Republicans have been tangling for the better part of a year over various House Republican requests for documents as they investigate both the probe of Hillary Clinton's emails and the motives behind the Russia investigation. In the middle of Thursday's hearing, Republicans voted to demand Rosenstein turn over sensitive documents to Congress.

But is tussling over classified documents a natural tension between Congress and the Justice Department or, as Rep. Jim Jordan (R-Ohio) tried to frame it, a sinister move by the Justice Department? “We have caught you hiding information,” Jordan accused.

Rosenstein pushed back on that. Hard. He got visibly upset, and he denied under oath that the Justice Department has any nefarious intentions.

“When you find some problem with production and questions, it doesn't mean I'm personally concealing something from you,” Rosenstein said. “It means we are running an organization that is trying to follow the rules.”

4. GOP argument: FBI agent Peter Strzok's personal bias affected the conclusion of the Hillary Clinton email investigation

Republicans have argued it's implausible that an agent who was near the top of both the Clinton email investigation and the Trump-Russia investigation demonstrated political bias against Trump in personal texts but didn't bring that bias to work.

But that flies in the face of findings from an independent report by the Justice Department's inspector general. The report said Strzok's texts weren't professional but found no evidence that Strzok's bias actually influenced the outcome of any investigation. He's since been removed from the Russia investigation.

Wray reiterated that Thursday: “My understanding of it is that [the inspector general] found no evidence of political bias actually impacting the investigation that he reviewed.”

Earlier in the hearing, Wray, unprompted, defended his agency from broad characterizations (made by the president) of bias: “This report is about a specific set of events and a specific set of employees. Nothing in this report impugns the integrity with our workforce as a whole or the FBI as an institution.”

On those texts, Rosenstein later added: “There were violations of the rules, I recognize that. . . . I can assure you that the cases that are brought under our watch are going to be under compliance of the rules. The folks we work with day in and day out there are almost all there to do the right thing.”

5. GOP argument: Rosenstein should recuse himself from the investigation

Getting rid of Rosenstein would get rid of a lot of Trump's self-professed problems. Rosenstein appointed Mueller and approves Mueller's work; Trump could appoint someone else to oversee the Russia investigation.

On Thursday, Rep. Ron DeSantis (R-Fla.) asked Rosenstein why he hasn't stepped aside if he oversaw parts of the investigation that DeSantis and Trump and allies think were skewed politically.

Rosenstein replied he had no reason to: “I can assure that, if it were appropriate for me to recuse, I'd be more than happy to do so and let somebody else handle this. But it's my responsibility to do it.”

Both Wray and Rosenstein, prompted by Rep. Steve Cohen (D-Tenn.), also took the opportunity to say they wouldn't bow to political pressure to leave their jobs.

Rosenstein: “Congressman, in the DOJ, we are accustomed to criticisms of our work, and it doesn't affect our work.”

Wray: “Congressman, as I've said repeatedly, I am committed to doing this job by the books in all respects, and there is no amount of political pressure that is going to dissuade me from that by either side.”