The top attorney for House Democrats is poised to play a key role in determining whether Democrats begin impeachment proceedings against President Trump.

Even though some of House counsel Douglas Letter’s legal fights are on topics such as ObamaCare and border wall funding, Speaker Nancy Pelosi (D-Calif.) has pointed to the lawsuits surrounding subpoenas for Trump’s private records as laying the foundation necessary for possible impeachment proceedings.

Whether to formally initiate impeachment will be left up to House Democrats, but the information Letter is seeking in court is being teed up as crucial to that decision.

However, it’s unlikely that the pressure is weighing too heavily on Letter, former colleagues told The Hill.

“I think he’s reveling in it,” said Bob Loeb, who served as Letter’s deputy at the Department of Justice (DOJ).

“He loves the big cases, he loves important matters. And I think he’s energized,” added Loeb, who is now an appellate partner at Orrick Herrington & Sutcliffe LLP.

Letter was described as an institution when he left the DOJ after 40 years, a reputation he carried into the House job eight months ago. Since January, he has argued in court — against DOJ attorneys and on behalf of lawmakers — in at least eight high-profile cases.

Those close to Letter, as well as former House counsels, describe him as a nonpartisan advocate for the law with decades of experience, giving him a wealth of knowledge to tap as he moves forward in the cases, particularly those concerning separation of powers issues.

“Working at the Justice Department — especially the kind of jobs that he’s had — gives you excellent exposure to a wide array of federal legal issues,” said Thomas Hungar, who served as House counsel from 2016 until this year. “Constitutional separation of powers, administrative law, the kinds of things that he’s dealing with.”

The lawsuits are also posing new legal challenges for the courts.

Judges are being presented with scenarios raising unique separation-of-powers concerns, like how far Congress can go in subpoenaing a sitting president. That opens the door for legal precedents to be set, meaning Letter isn’t just under pressure to win, but to do it in the right way as well.

However, there are concerns that Letter could have too much on his plate. The House general counsel’s office has a staff of six attorneys, in addition to Letter, as well as three law clerks.

And with Democrats’ investigations ramping up and the president digging in on his refusal to comply with the probes, the office’s workload is unlikely to slow down any time soon.

During one particularly busy stretch in May, Letter defended a subpoena for records from Trump’s private accountant in federal court in Washington, D.C. Three days later he was arguing in a California court against the Trump administration’s ability to use military funds for a wall on the southern border.

Less than a week after that, he was back in front of a federal judge in D.C., again fighting the border wall funding.

“There have been times in the past when the office had a lot of litigation, but I’m not aware of anytime when they had as many active litigated matters against the executive branch in the oversight and investigations area, as well as other matters,” Hungar said.

The House counsel’s office is also tasked with helping lawmakers and their offices when it comes to certain legal matters, like whether proposed legislation would hold up in court or if it would be in conflict with federal or state laws.

The caseload in Letter’s office became something of issue last month, when House Judiciary Committee Chairman Jerrold Nadler (D-N.Y.) said lawmakers were delayed in going to court to compel testimony from former White House counsel Don McGahn due to the amount of work presented to the counsel’s office.

Letter has tapped outside attorneys to help out in some cases. The law firm Munger, Tolles & Olson has assisted in the ObamaCare lawsuit, which Letter argued before the 5th Circuit last month, as has the Constitutional Accountability Center.

Georgetown Law’s Institute for Constitutional Advocacy and Protection (ICAP), where Letter briefly worked before becoming the top House lawyer, has helped the counsel’s office in the 2020 census citizenship question case, as well as one defending a federal ban on female genital mutilation.

Joshua Geltzer, the director of ICAP, predicted that Letter will turn to outside parties to help out in some cases down the line, while still recognizing that he’s the one who has to oversee the House’s legal efforts.

“I think he rightly views his role as the quarterback and as the person who ultimately needs to tell the Speaker of the House what the best view of the law and of litigation options might be,” Geltzer said. “You can be a quarterback with a lot of other players on the field. But ultimately, there’s still only one quarterback.

“And I think he’s very aware of it and has all of the right energy and acumen to play that role.”

The House passed a resolution in June that authorized Letter to bring in outside counsel to help manage future cases. That same resolution authorized House committee chairs to go to court to enforce subpoenas.

The House counsel has succeeded in getting many of the cases on an expedited schedule. But fast in the courts doesn’t necessarily translate to fast in politics, with fast-tracked lawsuits taking months to reach a conclusion.

Democratic leaders have said they don’t mind being patient. But the 2020 elections are looming, putting pressure on Letter’s office to score some quick victories.

Even more pressing, however, is the issue of impeachment. While some Democrats have been wary to throw their full support behind such an effort, a filing signed by Letter last week seeking grand jury material in the Mueller report prompted many lawmakers to argue they are already in an impeachment proceeding.

Grand jury information can be released by a judge only during specific situations, one of which is an impeachment proceeding.

“Because Department of Justice policies will not allow prosecution of a sitting President, the United States House of Representatives is the only institution of the Federal Government that can now hold President Trump accountable for these actions,” the House lawsuit states. “To do so, the House must have access to all the relevant facts and consider whether to exercise its full Article I powers, including a constitutional power of the utmost gravity — approval of articles of impeachment.”

Still, Pelosi has maintained that she will not proceed with any impeachment proceedings until lawmakers get the information at the heart of the subpoena lawsuits, like Trump’s private financial records and his tax returns.

“We will proceed when we have what we need to proceed,” she told reporters late last month. “Not one day sooner.”

Letter’s office runs under the direction of the Bipartisan Legal Advisory Group, a collection of the top five House lawmakers, including Pelosi. Her office did not make Letter available to be interviewed for this story.

Letter has managed to secure some key victories for Democrats. A pair of federal district judges have ruled to uphold congressional subpoenas after hearing arguments from Letter, and the panel at the D.C. Circuit Court of Appeals appeared to lean more toward the House counsel during oral arguments over one of the subpoenas earlier this month.

But not every case has gone his way.

A federal judge in D.C. rejected House Democrats’ lawsuit seeking to block Trump officials from diverting Pentagon funds for a border wall, ruling that the lawmakers can’t sue the executive branch. That finding is now being appealed.

The House counsel also seems to be facing an uphill battle to protect ObamaCare in a case Letter argued before a panel of judges on the 5th Circuit Court of Appeals last month. The House voted to intervene in the case after the Justice Department decided to stop defending the 2010 law in court.

“I think he approaches every case with the same sort of intensity, whether he thinks the panel is going to be favorable or not favorable,” said Matthew Collette, who worked with Letter at the Justice Department. “And so he’s always ready for the most difficult questions to come.”

Letter is a notable presence in the courtroom, employing a conversational style of argument. He comes across as approachable, allowing him to build a respectful rapport with the judges he’s trying to win over.

“He’s very respectful of the judges and I think you’ll always hear that in his tone,” Loeb said. “But I think that he wants to engage them as people. And so there is sort of a casual rapport there, which I think is and can be very effective.”

He’s not afraid to crack a few jokes either.

During oral arguments in D.C. over the administration’s use of military funds for Trump’s border wall, Letter joked that he and the Justice Department lawyer were going to switch sides — they had argued against each other in San Francisco just six days earlier in a similar case.

Last month, Letter caused a D.C. courtroom to break out in laughter when he jokingly promised that the House will “never” subpoena the childhood diary of a president.

Letter’s leadership style isn’t contained to the law. He’s long organized a Tuesday night basketball game in D.C. with other lawyers.

“He’s a point guard type, he distributes the ball well,” said Geltzer, who also used to work with Letter at DOJ. “He’s not going down to the low post and powering anybody in, but he can run the offense pretty well.”

And those skills on the court translate nicely into the courtroom, Geltzer said.

“He is tireless, there’s no such thing as burnout.”