House prosecutors and defense lawyers arguing the case against President Trump may be turned into de facto witnesses, as Republican and Democratic senators plan to use part of their question time to press counsels on their personal involvement at pivotal moments of impeachment.

For Republicans, the target is House Intelligence Committee Chairman and lead manager Adam B. Schiff (D-Calif.), whom Trump has called on to testify about his panel’s interactions with the anonymous whistleblower who flagged the president’s July 25 phone call with Ukrainian President Volodymyr Zelensky.

Democrats, for their part, are eyeing White House counsel and co-lead Trump defense attorney Pat Cipollone, whom House managers asserted is a “material witness” because of his signature on an Oct. 8 letter laying out how the administration would stonewall the House’s impeachment inquiry, denying evidence and witnesses.

Neither lawyer has been called to testify in the trial, which may conclude with or without witnesses, as senators argue over whether former national security adviser John Bolton and others should testify after leaked revelations from Bolton’s forthcoming book. But as senators get their first opportunity to query the managers and Trump’s legal team, there is a push to demand a reckoning from those who have played a role in the third impeachment in U.S. history, as the parties try to give each side a chance to repeat their best points or offer rebuttals.

“There ought to be an opportunity to question any of the lawyers about what they knew and when they knew it,” said Sen. Richard Blumenthal (D-Conn.).

The crux of the case is the allegation that Trump tried to leverage military aid and a White House meeting for Zelensky in exchange for investigations of Joe Biden, the former vice president and 2020 candidate, and his son Hunter.

Senators have up to 16 hours, divided over two days beginning Wednesday, to pose questions to either the House managers or the Trump defense team. The lawyers will be given up to five minutes to respond to each query.

Each side faces a balancing act in its allotted time.

Senate Republicans must weigh the desires of moderates, who want to ask factual questions that could help determine whether to vote to call witnesses, against those of Trump loyalists, who want to pose questions that will allow defense lawyers to double down on attacks against Democrats, according to multiple GOP officials.

“I would certainly anticipate at least some of the questions will be specific for Adam Schiff. That’s how the process is designed,” said Sen. Ted Cruz (R-Tex.), giving a nod to questions related to Schiff and the whistleblower in particular. “I would be surprised to go through 16 hours of senator questioning without anyone bringing that up.”

Schiff has said he never talked to the whistleblower and doesn’t know the individual’s identity. When the whistleblower contacted the Intelligence Committee, the person was told to seek legal counsel and reach out to the intelligence community’s inspector general, Schiff has said.

But if he or other House managers are targeted, “it will open up Pat Cipollone and other White House lawyers — actual fact witnesses, unlike any of the House managers — to potential questions about their actions to cover up the president’s impeachable conduct,” a senior Democratic official working on the impeachment trial said, quoting Trump lawyer Jay Sekulow’s admonition: “Be careful what you wish for.”

Sen. Kevin Cramer (R-N.D.) said he is “curious for a better explanation as to why they [House investigators] didn’t pursue particularly Rudy Giuliani and his documents, and maybe there’s good reason for it. And then the same for Bolton, I guess, that’s become more interesting all the time because he’s become such an epicenter — but yet they really gave up easily on getting him to testify when he seemed to want to testify.”

In fact, the House committees asked Bolton to testify, and he turned them down.

For Democrats, the chief objective is ensuring that their questions create an opportunity for House managers to respond to the Trump team’s arguments.

“There are going to be plenty of means for the House managers to rebut and conclude in that question period,” said Sen. Chris Murphy (D-Conn.).

“We can ask questions that are in effect an invitation to set the record straight,” Blumenthal said. “Some of the questions will be obvious in giving the managers an opportunity essentially to push back or correct the record.”

But many Democrats also want to use their time to challenge Trump’s team on what they believe are a series of misrepresentations — including how much his lawyers knew about Bolton’s assertions that Trump held up Ukraine aid to secure an investigation of the Biden family, when they were claiming there was no quid pro quo.

“If the White House was aware because they got a copy of this book prepublication, and they know what the book is going to say, when they look me in the eye and say, ‘There’s no testimony quid pro quo’ . . . I feel misled,” said Sen. Tim Kaine (D-Va.). “I feel like they’re trying to pull the wool over my eyes. . . . I don’t like it when a lawyer looks like they’re dodging or hiding stuff.”

Senators may direct questions at representatives on either side, but they cannot select which manager from the prosecution or lawyer from the defense answers them. It is also unclear whether Chief Justice John G. Roberts Jr. would force representatives to answer questions if they did not relate directly to evidence that has been presented in the trial — a potentially complicating factor for any senators who wish to pin down Schiff, Cipollone or others as if they were fact witnesses.

But part of the allure of turning the spotlight on lawyers is that neither side has at their disposal the testimony of fact witnesses they believe are central to the case. Leading Senate Republicans have opposed calling witnesses altogether, and Senate Democrats have rejected a proposal from rank-and-file Republicans for a one-for-one arrangement, arguing that they will not barter Bolton for someone like Hunter Biden when others — such as acting White House chief of staff Mick Mulvaney and Office of Management and Budget officials Robert Blair and Michael Duffey — are also critical to their case.

Some senators may try to focus attention on the need for testimony from those individuals by asking about documents that have emerged since the House voted on impeachment articles — such as materials from Lev Parnas, who worked closely with Trump’s personal lawyer Giuliani to press Ukrainian officials to announce an investigation of the Bidens.

“I think Parnas raises issues about some of the people around the president,” Sen. Ben Cardin (D-Md.) said. “To me, it brings up Mulvaney again, it does bring up Bolton, it does bring up the need to have those witnesses.”

But other senators have raised doubts about whether the question-and-answer period will yield any revelatory information and about the value of directing questions at lawyers whom they don’t trust.

“There’s some questions that I have regarding what manager Schiff had represented early on about there being eight quid pro quo examples in the telephone call, which we now know is not true,” said Sen. David Perdue (R-Ga.).

“I quite frankly think their team will not try to honestly answer everything we ask them, which is the challenge, isn’t it?” Sen. Jeff Merkley (D-Ore.) said of Trump’s defense. “It’s not like they answer and you get a follow-up. We’ll see how valuable these questions are, or aren’t.”

Under the process, Republicans, who hold the majority in the Senate, are expected to go first, and the sides will alternate until time is up or the questions have been exhausted.

Senate Majority Leader Mitch McConnell (R-Ky.) and Senate Minority Leader Charles E. Schumer (D-N.Y.) will field questions from their respective parties, sorting and organizing the proposed queries to try to impose some order.

During the session, Democratic senators are expected to each stand when it comes time to offer their questions; they will hand a card with the handwritten query to a page, who will deliver it to the Senate parliamentarian, who will then give it to Roberts, who will read it. Republicans also will submit questions in writing.