Lawyers for Trump say the appointment of a special master is necessary to ensure an independent inspection of the documents. This kind of review, they say, would allow for “highly personal information” such as diaries or journals to be separated from the investigation and returned to Trump, along with any other documents that may be protected by claims of attorney-client privilege or executive privilege.

The Justice Department says an appointment is unwarranted because investigators have completed their review of potentially privileged records and identified “a limited set of materials that potentially contain attorney-client privileged information.”

The government says Trump lacks legal grounds to demand the return of presidential documents because they do not belong to him. The department has also expressed concerns that the appointment could delay the investigation, in part because a special master probably would need to obtain a security clearance to review the records and special authorization from intelligence agencies.

U.S. District Judge Aileen Cannon said she would issue a written ruling at some point.

Cannon had said on Saturday, before the latest arguments in the matter, that her “preliminary intent” was to appoint a special master. It was not clear whether she might make a final determination Thursday or how her view might be affected by the fact that the Justice Department says it has already reviewed potentially privileged documents.

It was also not clear who might be serve as that outside expert. In some past high-profile cases, the role has been filled by a former federal judge.

Cannon was nominated by Trump in 2020 and confirmed by the Senate 56-21 later that year. She is a former assistant U.S. attorney in Florida, handling mainly criminal appeals.

—Tucker reported from Washington.