(CNN) A federal judge's move to bring in a special master to review materials seized from former President Donald Trump's home has opened up an extraordinarily murky, sensitive and high-stakes task of finding an attorney to serve in that role and defining what exactly he or she will do.
The person who US District Judge Aileen Cannon ultimately chooses will have access to documents that have been described as among some of the government's most sensitive secrets. And they may have very little guidance.
On Friday, the Justice Department and Trump's lawyers will file legal briefs laying out their proposed candidates, along with recommendations for how the review should proceed.
Cannon issued an order Monday granting a request from Trump that a special master -- i.e., an attorney from outside the government -- sift through the documents obtained in the FBI's search of Mar-a-Lago for potentially privileged items.
The Justice Department has previously asked the court to appoint an attorney who already has the top secret security clearance usually required to review the classified materials seized. But that narrows the pool of potential candidates -- and finding one acceptable to both sides within that limitation may prove complicated. Outside legal observers have said that a former federal judge might be an ideal candidate, given the experience veterans of the bench often have with dealing with classified materials as well as the reputation of neutrality they'd bring to the role.
But that is only one part of the challenge: What exactly the attorney will be asked to review in the documents for has been left largely unclear by Cannon's order.
According to the order, the review will include materials covered by executive privilege -- a legal gray area that has been perhaps the source of the sharpest contention in the case.
"The problem is the parties will not come to an agreement, because there's no incentive for either party to agree to the other party's view," said Alan Rozenshtein, a former attorney in the DOJ National Security Division who is now a University of Minnesota law school professor.
The Justice Department has called the review "unprecedented."
"Finding someone to do it is not easy, but not the most difficult thing," said Jonathan Shaub, a former Justice Department attorney. Shaub told CNN it will be even harder for the parties and the court to hash out what the parameters of the review will be.
"It's going to be hard for the court, because I don't think the court understands what executive privilege entails," added Shaub, now a law professor at the University of Kentucky.
The Justice Department vehemently opposed the appointment of a special master, and it may well still appeal Cannon's order -- in large part because it blocks them from continuing with certain aspects of the criminal investigation into the handling of the documents.
In addition to the attorney-client privilege concerns special masters typically focus on, Cannon said in her Monday order that she was also allowing a review for executive privilege as she said it remains an open legal question whether a former president's assertions the privilege can overcome the refusal to do so by the current office holder -- a matter of fierce disagreement among legal experts.
In this case, President Joe Biden left it up to the National Archives to decide whether it would abide by Trump's assertions of privilege and the Archives concluded it was not obligated to, according to court filings. Even in the contexts that executive privilege typically comes up -- such as in Freedom of Information Act litigation or congressional pursuits for information -- there's much dispute over the breadth of its scope.
Some see it limited as to the communications between a president and his top advisers, while the Justice Department has argued in those kinds of case that it covers all sorts of internal executive branch deliberations as well as attorney-work product and national security privilege.
The Mar-a-Lago case adds in a novel complication because Trump is asking for executive privileged material to be withheld from the executive branch itself.
The special master review will also search for documents protected by attorney-client privilege -- a far less unusual order, although typically such reviews are conducted when the office of an attorney has been searched.
This uncharted territory -- and what critics say is a vaguely written order by Cannon -- has left huge questions about what, exactly, the special master will be looking for once he or she accesses the seized materials.
Both parties are expected to submit by Friday a brief proposing the special master's "duties and limitations."
"You know that the Trump team is trying to put a broad scope of review in its version of the appointment order," Kel McClanahan, a national security lawyer and an adjunct professor at the George Washington University Law School, told CNN.
But if the Justice Department puts forward an extremely narrow argument for what the executive privilege should cover, it risks having those arguments used against it in transparency disputes down the road.
But the first hurdle is finding a candidate with whom the government feels comfortable sharing some of its most sensitive secrets.
In court filings, it said that if a special master were to review classified material, he or she would need to "already possess a Top Secret/SCI security clearance."
"We treat [the documents] presumptively as classified. We would not turn them over to somebody that does not have the appropriate clearances," DOJ attorney Jay Bratt said at a hearing in the case last week.
Trump's lawyer called the concerns a "bogeyman."
"If there is a special master that doesn't have clearance, it can be expedited" by the Department of Justice, Trump attorney Jim Trusty argued. "It doesn't have to take weeks or months. It can be done very quickly, particularly with a gentle prod from this Court."
Some legal experts suggested that the government may decide it's worth forgoing some of the protocols a person would usually have to go through in the interest of getting the special master review started quickly.
Some of the documents picked up in the search may be so sensitive -- such as records concerning foreign nuclear capabilities described in a Washington Post report -- that it may, counterintuitively, broaden the pool of who the government will find acceptable from a clearance standpoint, according to Rozenshtein.
"It's almost so sensitive that you're just going to take a national security risk, no matter who you pick as a special master," he said, calling it an argument for "just picking someone really respected and renowned because there's almost no amount of vetting that is going to make this fundamentally appropriate."
If the judge does decide to choose a special master who already maintains an active Top Secret security clearance, he or she will still need to be given access to the specific program at issue for some of the documents. Some of the documents recovered from Mar-a-Lago contain what is known as "compartmented" information -- information that is restricted to a certain group of clearance holders on a need-to-know basis, rather than information that is available to anyone with a Top Secret clearance.
But that process is relatively simple, according to Brad Moss, an attorney who specializes in federal employment and security clearance law.
"This largely can be handled with just some extra paperwork and security briefings," Moss said in an email to CNN. The special master would be "read on" to specific programs -- all work that would need to be done in a secure facility, or SCIF -- and then sign briefing acknowledgment forms and likely additional nondisclosure agreements, he said.
The process would get more complicated if the special master doesn't have an active -- or at minimum recent -- clearance. Depending on how long ago the Special Master was last "adjudicated" for his or her clearance, the government might require an additional SF-86 form, the standard background check questionnaire national security professionals are required to fill out to obtain their clearances.
Moss said that it is also possible -- although unlikely given the limited involvement the special master would have with the documents -- that the government may also require a polygraph, as is usually required for someone being granted access to compartmented information.
If the special master has staff helping him or her, they will have to go through the same process.
A retired judge may be a particularly attractive candidate, several legal experts said, as many veterans of the bench have already had to deal in classified materials as part of the cases they have dealt with. Judges are not necessarily granted a security clearance to do so, but the government may feel comfortable with a retired jurist accessing the materials given that those officials were likely trusted with government secrets when they were on the bench.
"I would imagine there are judges who are qualified, but I can't imagine it's a very large pool," said Daren Firestone, a former DOJ attorney.
Even if the government can be satisfied, the Trump team may not be. Outside observers said the types of recent government exiles who fit the bill from a security clearance standpoint may be seen as objectionable to the Trump team, which has thrown sensational accusations of political bias.
"Ultimately, the potential pool of candidates would likely not be too difficult for the Department of Justice to identify. The issue is going to be which of those candidates would be palatable to the former president's attorneys," said Brandon Van Grack, a former attorney in the national security division at the Justice Department.
The choice, in the end, will be Cannon's.