While this happens to some degree in every presidential transition, and some political appointees make for perfectly capable public servants, Biden aides, lawmakers, labor groups and watchdog organizations are sounding the alarm — warning that in addition to standard burrowing, the Trump administration is leaning on a recent executive order to rush through dozens if not hundreds of these so-called “conversions.” The fear is that, once entrenched in these posts, the Trump bureaucrats could work from the inside to stymie Biden's agenda, much of which depends on agency action.

The October executive order — which Biden is expected to swiftly rescind — has allowed federal agencies to help political appointees circumvent the usual merit-based application process for career civil service jobs, while moving career policymakers into a new job category with far fewer legal protections.

Thanks to weak transparency laws, the full impact of both changes may not be known for months.

The Office of Personnel Management is required to report any conversion of political appointees into career positions to Congress on a quarterly basis — meaning lawmakers only know now what has happened through September of last year. But there are also gaps in terms of which agencies must be included in the reports, which are not required to be made public. The disclosures are also dependent on agencies identifying the employees shifting into career slots and reporting them to OPM.

“There’s real questions about whether OPM has served as a true guardian to stop bad conversions from happening,” said Max Stier, president and CEO of the Partnership for Public Service, a nonprofit focused on improving the way government works.

The president-elect and his team are aware of the issue and have been considering ways to address it, several officials involved with or close to the transition told POLITICO. Transition officials have discussed whether and how Biden could fire burrowed employees and if they should ask inspectors general to get involved, one person said.

They have also asked their agency review teams to look out for burrowing at the departments they are overseeing, and the teams have provided transition leaders with regular updates on any appointees being converted to civil servant positions or other cases of political hiring.

"The incoming Biden-Harris administration is keenly aware of last minute efforts by the outgoing administration to convert political appointees into civil service positions," a transition official said in a statement to POLITICO. "We anticipate learning more in the weeks ahead as our work to restore trust and accountability across the federal government begins, including reviewing personnel actions taken during the Trump administration."

A third person close to Biden said officials with the incoming administration are worried that they’ll have to juggle rooting out Trump holdovers with efforts to get the new Cabinet in place and move aggressively to combat the pandemic and economic crisis.

“We’ve identified some people already, but we don’t know how many there are in total, or where exactly they’re placed,” the person said. “The incoming administration will have to evaluate it and think about alternative placements [for the burrowers], and that will take time and create more distractions and burdens for them.”

Some Trump appointees are already on the radar of the Biden team, Democrats in Congress and outside groups.

Among them is Michael Ellis, a former staffer of Rep. Devin Nunes (R-Calif.), who helped House Republicans gain access to classified information during Trump’s first impeachment investigation and who will be installed this week as the National Security Agency's top lawyer. The director of the agency opposed Ellis' conversion, but was overruled by Trump's acting Defense Secretary Chris Miller. Speaker Nancy Pelosi wrote to Miller on Monday demanding he cancel Ellis' installment, calling it "highly suspect."

"The efforts to install him or 'burrow' him into a highly sensitive intelligence position 72 hours prior to the beginning of a new Administration manifest a disturbing disregard for our national security," she wrote.

Also on Democrats' watch list is Brandon Middleton, a former Senate staffer for Jeff Sessions who Trump appointed to be a deputy solicitor at the Interior Department in 2017. Last year, Middleton was converted into the chief counsel at the Energy Department — a career position.

“He has the kind of background that makes me concerned that he might use his new career position for ideological purposes,” Nick Schwellenbach of the Project on Government Oversight said of Middleton. “There are some political appointees who are qualified and are experts and are the best picks for the job, but whenever it happens, it needs to be reviewed very closely to make sure they are not just hacks who are burrowing in.”

In December, Democratic senators wrote to the Justice Department demanding information on the hiring of gun rights advocate John Lott to serve as a senior adviser in the Office of Justice Programs, a move they said gives them “concerns about the Department’s compliance with requirements designed to maintain the continued integrity of the nonpartisan career civil service.”

And just last week, the U.S. Chemical Safety and Hazard Investigation Board announced that David LaCerte, a Trump appointee who had been serving as deputy associate director at the Office of Personnel Management, would be joining the agency for a three-year term as a senior adviser and executive counsel. Public Employees for Environmental Responsibility, a nonprofit that supports government workers who protect the environment, flagged the move as a “political hire” of an “unqualified crony senior executive.”

One USAID official told POLITICO that staff are hesitant to speak out about the level of burrowing taking place, saying that "everybody is fearful of retaliation" at a time when the Trump administration is moving to strip protections from some career officials in its final days in office.

Once Biden’s team does identify the Trump holdovers that have burrowed into career positions, they can try to challenge those conversions, but would have the burden of proving that the person was not qualified for the position or that a career applicant was improperly passed over for the job. They can also request that the Office of Special Counsel look into whether individual conversions violated civil service law.

But outside of those time-consuming avenues, there isn’t much they can do, and if the people make it unscathed through the usual one-year probationary period for all new career employees, they can only be dismissed for serious misconduct.

The most likely tactic, said sources on Capitol Hill and in Biden's circle, is to reassign the individuals so that they don't have access to sensitive information or influence over major federal policies.

“Our options to respond to burrowing are really limited, which is why they do it,” one Democratic aide working on the issue told POLITICO. “It’s like whack-a-mole. Once you have found them, you can’t fire them. Your recourse is to transfer them to somewhere they don’t want to be, isolate them, and make working conditions bad to the extent you can, without crossing lines put in place to protect the civil service.”

Lawmakers in charge of government oversight in the House and Senate say they’re running into roadblocks as they’ve tried to obtain information about the Trump administration appointees who are burrowing into the civil service.

In October, Democrats asked the Office of Management and Budget to turn over all documents about Trump’s executive order on the civil service, saying they feared it would bring about “a blatant return to patronage politics and a federal workforce based on cronyism and nepotism.” The agency responded in December to say that they had already briefed Congress on the impact of the new policy and wouldn’t be sharing more information, according to a letter shared with POLITICO.

In November, the same lawmakers asked the Government Accountability Office to investigate “the hiring of political appointees into jobs without regard to merit ... in roles best served by career civil servants,” but have yet to receive a report. They’re also calling on Biden to rescind the Trump administration’s executive order that made the conversions easier and “work with Congress to address the malign effects.” They also sent letters to 61 different federal agencies asking for full lists of all conversions of political appointees.

“My primary concern is the damage to the long tradition of a nonpolitical civil service,” said Rep. Gerry Connolly (D-Va.), one of the leaders of the push. “I fear that that’s happening.”

Given the challenges of tracking the number of Trump loyalists installed deep within the ranks of the civil service, it’s virtually impossible for Biden’s team to know at this point exactly how much of a problem they will face once in office. But groups representing federal workers say that what they’ve learned so far is troubling.

“There are more conversions over the past four years, and more significant conversions, than there have been in the past,” said Jason Briefel, the director of policy and outreach at the Senior Executives Association. “There is supposed to be a merit system and rules to ensure that politics isn’t the primary thing driving who gets a job. But we don’t have the mechanisms to ensure that anymore.”

Briefel added that he’s concerned the issue could undermine staff morale as Biden’s team works to combat a still-raging pandemic with a hollowed out and demoralized federal workforce.

“If there’s latent bad blood between the careers and people who have burrowed in … it makes an already sensitive time even harder,” he said.

Stier, of the Partnership for Public Service, said he was “not aware of any modern presidency in which there have been as many questions about, or as many apparently inappropriate hirings, as there have been in this administration."

One person in touch with the transition team put it more simply. “Like anything,” the person said, “it’s more of a problem with Trump.”

Daniel Lippman contributed to this report.