The impeachment inquiry into President Donald Trump spilled over Wednesday into an unrelated Senate Armed Services subcommittee hearing, where senators pressed the Defense Department’s second-highest official about protections for witnesses and whistleblowers.

Sen. Tim Kaine, D-Va., asked Deputy Defense Secretary David Norquist about news reports that the Army was considering extra security for the family of Army Lt. Col. Alexander Vindman, who testified in the impeachment probe on Tuesday.

Vindman, who has been detailed to the National Security Council where his portfolio includes Ukraine, has said he raised concerns over the July 25 phone call between President Trump and Ukrainian President Volodymyr Zelenskiy that is at the heart of the impeachment inquiry.

“I’m not going to ask you whether you think it’s appropriate to attack his loyalty, his patriotism, his judgment or his character, because I know how you would think of such an attack,” Kaine said, noting that Vindman and Norquist are both Virginia residents and therefore Kaine’s constituents. “In your role as deputy secretary of Defense, will you make sure that members of the military are not punished or face reprisals for cooperating with Congress?”

Norquist declined to elaborate on what steps the Defense Department may or may not be taking to protect Vindman. But he did say the department takes its responsibility to respond accurately to Congress very seriously.

[Republicans abandon tradition of whistleblower protection at impeachment hearing]

“We expect people to be responsive and truthful in their dealings with Congress,” said Norquist, who had been prepared for a far wonkier discussion on the results of the Pentagon’s second audit.

Sen. Mazie K. Hirono, D-Hawaii, asked Norquist about a letter that he sent to the attorney of Defense Department official Laura Cooper, who the House Intelligence Committee deposed behind closed doors Oct. 23 after being subpoenaed. Cooper, the deputy assistant secretary of Defense for Russia, Ukraine and Eurasia, is scheduled to testify publicly later Wednesday.

“This letter informs you and Ms. Cooper of the Administration-wide direction that Executive Branch personnel cannot participate in [the impeachment ] inquiry under these circumstances,” the Oct. 22 letter states, referring to the White House’s official response to the inquiry. “In the event that the Committees issue a subpoena to compel Ms. Cooper’ s appearance, you should be aware that the Supreme Court has held … that a person cannot be sanctioned for refusing to comply with a congressional subpoena unauthorized by House Rule or Resolution.”

Norquist said he sent the letter to inform her lawyer of the White House position, since the Defense Department would not be able to send its own lawyer with her. The Defense Department, he said, tried to strike the right tone of being professional and factual in the letter.

Hirono asked what additional steps Norquist had taken to send a clearer message to Defense Department staff that their identities and jobs will be protected if they come forward to report abuse or misconduct.

“When people come forward, we expect them to be honest and truthful in their dealings, and we expect them to be taken care of in doing so,” Norquist said.

Hirono urged the Pentagon to send a message from top leaders that whistleblowers will not face retribution, and she hoped the Defense Department would not try to stop any of its personnel from cooperating with the inquiry going forward.

Norquist said he was unaware of anyone else who had been subpoenaed.

“We understand each of the individuals is making their own decision,” Norquist said.

It is worth noting that the Defense Department itself has refused to comply with a congressional subpoena requesting documents and materials related to the withholding of security aid, some of which had been appropriated by Congress to the Pentagon to pass along to Ukraine.