Sen. Ted Cruz blasted former Deputy Attorney General Rod Rosenstein’s role in the Russia investigation during a tense Senate hearing Wednesday, saying he was either “complicit” or “grossly negligent.”

Rosenstein appeared before the Senate Judiciary Committee as the first witness as in the panel’s new investigation into the origins of the Russia probe, and acknowledged misconduct surrounding the probe—testifying that he would not have signed a surveillance warrant renewal application for former Trump campaign aide Carter Page had he known about the since-revealed problems surrounding that process.

ROSENSTEIN TESTIFIES HE WOULD NOT HAVE SIGNED FISA WARRANT FOR TRUMP AIDE IF HE KNEW OF PROBLEMS

But the hearing room soon became a combustible environment, with Rosenstein used as a punching bag for lawmakers on both sides of the aisle. Cruz, R-Texas, pressed Rosenstein on why he didn’t ask more questions about the probe he once oversaw, which he described as one of the most important investigations at the DOJ at the time.

Cruz described the Justice Department, upon Rosenstein’s arrival as deputy attorney general, as “corrupted and politicized.”

Cruz went on to list Rosenstein’s actions as deputy attorney general with regard to the Russia investigation—including his May 17, 2017 appointment of Robert Mueller as special counsel; his June 29, 2017 signing of the FISA warrant renewal for Page; and his Aug. 2, 2017, “scope” memo for Mueller’s investigation.

“You came into a profoundly politicized world and yet, all of this was allowed to go forward under your leadership,” Cruz said. “That, unfortunately, leads to only two possible conclusions—either you were complicit in the wrongdoing, which I don’t believe was the case, or that your performance of your duties was grossly negligent.”

Rosenstein chuckled at Cruz’s characterizations, and said that “you always wish you could have done more.”

"But we did have 70,000 cases filed that year,” Rosenstein said. “I devoted more attention to this case than anything else, but I still didn’t know everything and that is the best I can give you, senator.”

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Rosenstein repeatedly claimed Wednesday to be unaware of details that have since been used by critics to raise questions about the probe. Rosenstein said he "obviously didn’t know there was exculpatory evidence" with regard to the Russia investigation, including details about Michael Flynn and George Papadopoulos.

Meanwhile, committee Chairman Lindsey Graham, R-S.C., asked Rosenstein Wednesday: “If you knew then what you know now, would you have signed the warrant application?”

"No, I would not," Rosenstein said.

Graham also prompted Rosenstein to acknowledge there was scant collusion evidence in August 2017.

"The whole concept that the campaign was colluding with the Russians, there was no there there in August 2017. Do you agree with that statement?" he asked.

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Rosenstein replied: "I agree with that general statement.”

August 2017 is when Rosenstein penned the “scope memo” for Mueller’s investigation, which outlined the authority of Mueller. Last month, the memo was released in full, and revealed for the first time that Mueller’s authority went significantly beyond what was previously known.