The subject was raised by several Democratic senators on the Foreign Relations Committee to suggest further that Waltz was unqualified to fill Trump’s last remaining Cabinet post.

“The use of signal is not only … authorized, it was recommended in Biden’s binary system guidance,” Waltz said while answering a series of questions from Sen. Chris Coons (D-DE). “We followed the recommendation, almost the demand, to use end-to-end encryption, but there was no classified information shared.”

Coons expressed dissatisfaction, saying he’d been “hoping to hear from you that you had some sense of regret over sharing what was very sensitive, timely information about a military strike on a commercially available app.”

Sen. Cory Booker (D-NJ) later piled on Waltz for what the senator described as the nominee’s “failure to stand up and take accountability.”

“I heard you just blame Biden. I’ve seen you not only fail to stand up but lie,” Booker said. “I’ve listened to you now for weeks and months. You said this journalist intentionally infiltrated that stable chain. You said that he was sucked in, you denied, deflected, and then you did something that, to me, really lacks integrity, [which] is that you sought out to demean and degrade that very journalist in crass and, frankly, cruel ways that made him a target.”

There are two Department of Defense investigations into the Signal chat saga and one investigation already concluded by the White House. The first Pentagon inquiry is by the inspector general’s office, and the second is the Air Force Office of Special Investigations. The Air Force’s only became public this week, confirmed by the Washington Examiner.

“AFOSI is conducting an investigation into allegations of unauthorized disclosures of information on behalf of the Office of the Secretary of Defense,” an Air Force spokesperson told the Washington Examiner. “To protect the integrity of our investigations, we cannot comment on the specific details of any particular investigation.”

Waltz is accused of creating the Signal chat and adding an Atlantic magazine journalist, who later reported on the sensitive information published in the chat by Defense Secretary Pete Hegseth.

Waltz briefly acknowledged the DoD investigations and the closed inquiry by the White House. He insisted his removal as national security adviser was not a firing and noted he’s remained an administration employee since he was nominated to be U.N. ambassador in May.

“I shouldn’t and can’t comment on ongoing investigations,” Waltz said in a response to criticism from Sen. Tim Kaine (D-VA). “What I can do is echo Secretary Hegseth’s testimony that no names, targets, locations, units, routes, sources, methods — no classified information was shared.”

Kaine responded: “At a minimum, [the chat shared] attack planes with sensitive military information [that] shouldn’t have been shared.”

With the GOP’s three-seat Senate majority, Waltz is still expected to be confirmed with a simple majority. But it’s unclear whether he may face some Republican opposition from Sen. Rand Paul (R-KY), who could force the Foreign Relations panel to deadlock the nomination and force it to be discharged using a floor vote.

Paul, a libertarian, chided Waltz for a 2020 amendment vote when he served in the House to hinder Trump’s ability to withdraw U.S. troops from Afghanistan.

MIKE WALTZ TO FACE SIGNALGATE GRILLING IN HEARING TO FILL LAST TRUMP CABINET POST

“I guess it just worries me that you come more from the [former Rep. Liz Cheney] wing of the party than the Donald Trump party,” Paul said, referencing the amendment proposed at the time by the former Wyoming GOP congresswoman.

Waltz responded that he was “squarely with the president” on past and current foreign policies.

Mike Brest contributed to this report.