Reed pressed Hegseth on reporting war crimes and his role in pushing for Trump to pardon or promote men accused or convicted of war crimes.

“As someone who’s led men in combat directly and had to make very difficult decisions, I thought very deeply about the balance between legality and lethality, ensuring that the men and women on the front lines have the opportunity to destroy with and close the enemy and that lawyers aren’t the ones getting in the way,” Hegseth said.

He added that he was not discussing the Uniform Code of Military Justice or Geneva Conventions, but rather “restrictive rules of engagement” that have “made it more difficult to defeat our enemies.” Hegseth claimed that there was evidence withheld and prosecutorial misconduct in the cases Reed referred to.

Reed finished his questioning by asking Hegseth what a “jagoff” is, which Hegseth defined as an officer within the Judge Advocate General’s Corps “who puts his or her own priorities in front of the war fighters.” Jagoff is a derisive term meaning a stupid person.

In a tense exchange, Reed asked Hegseth if he was “aware” of reports that current serving military personnel had received emails “threatening them with being fired for supporting the current Department of Defense policies.”

Reed stated that one such email to a military officer that he’d been made aware of read, “with the incoming administration looking to remove disloyal, corrupt, traitorous, liberal officers such as yourself, we will certainly be putting your name into the list of those personnel to be removed.”

Hegseth said, “certainly I’m not aware of that — it’s not one of my efforts” before diving into his focus on “accountability.”

As Democrats begin their questioning of Hegseth, he's almost certain to hear lines of inquiry that have come up in his prep sessions. A source familiar says Hegseth has run “murder boards,” including as recently as last week, to get ready for today’s high-profile hearing.

Reed said he believes the FBI’s background investigation into Hegseth was insufficient for a nominee with “very complicated personal issues.” Reed and Wicker were the only two panel members to be granted access to the FBI report, which they received late last Friday.

Reed requested that there be a second round of questions presented to Hegseth before the hearing finishes.

"Many of my members would like a second round," Reed said after Wicker finished his first set of questions, adding that in his recollection, the committee had "never den[ied] anyone the opportunity to ask a second round of questions."

Wicker pushed back, telling Reed that he believed there would be "adequate time" for questioning.

"We're following the same exact precedent on all things that we did with Secretary Austin, so I respectfully understand what you're saying, but I think we have an agreement," Wicker said. "It's been known for quite some time, and I intend to stick with that agreement, which we made last December."

Wicker focused his first question on accusations against Hegseth, which he said came from "anonymous sources in liberal media." Hegseth said that there was a "coordinated smear campaign orchestrated in the media against us."

Hegseth’s opening remarks were interrupted three times by protesters but he followed his prepared opening statement almost exactly as it was written, emphasizing that "my only special interest is the warfighter."

Hegseth's opening statement was interrupted by three protesters, all of whom were escorted from the room.

The first protester could be heard calling Hegseth a "Christian zionist."

After the man, who was taken by officers and physically removed from the room, a woman in the audience began yelling moments later about “bombing babies in Gaza."

Trump's incoming White House national security adviser Mike Waltz, still serving in the House, introduced and endorsed Hegseth for defense secretary.

"Like Pete, I served in the U.S. Army. Like Pete, I'm a veteran," Waltz said. "We deployed to Afghanistan and all over the world at the height of the war on terror, which is the war of our generation, and like thousands of other war fighters, we have witnessed the hardships of war. We have experienced the loss of friends in combat. We have endured too much time away from family and friends."

Waltz said that Hegseth can "reinvigorate" warrior ethos and said he's "a man that will lead. I can't imagine having a more capable partner in my position as national security adviser."

Waltz and former Sen. Norm Coleman, R-Minn., who also introduced Hegseth, claimed that military recruitment is down, but it actually rose sharply last year.