The decision by a Florida judge to appoint a special master to review documents that former President Donald Trump kept at his Mar-a-Lago resort could lead to a legal battle that could delay the investigation for months and force it to the Supreme Court, according to Insider.

Raymond Dearie, a 78-year-old former chief judge of the US District Court for the Eastern District of New York, was appointed as the special master by Judge Cannon.

Cannon's initial decision to appoint a special master was appealed by the DOJ last week.

At the end of this week, the DOJ elevated its ask to the 11th circuit appeals court and requested a partial stay on Cannon's decision, as it prepares a formal appeal.

Cannon said that the special master's review should conclude by November 30, but due to the DOJ's appeals process, a legal tussle over what the special master can and cannot do may be elevated to the Supreme Court.

The case could make its way to the Supreme Court

The DOJ said in its latest request for a partial stay that the decision to allow classified documents to be reviewed by a special master before the criminal probe can continue "hamstrings that investigation and places the FBI and Department of Justice under a Damo clean threat."

A national security expert told Insider that the case will be affected by how quickly certain appeals are decided.

The National Security program at the Antonin Scalia Law School at George Mason University will be tested by the 11th Circuit. The case will be looked at by the appeals court to see if it should be sped up.

The appeals process could take months or a year if things aren't sped up.

The party wants the court of appeals to move quicker. "They can, they do that on a regular basis." Cannon's order could be stayed by the court of appeals.

The case could go to the Supreme Court if either Trump's team or the DOJ appeal a judge's decision.

The special master's review could go on, despite appeals

If the appeals court rejects the partial stay on Cannon's ruling, the DOJ will appeal. Unless a higher circuit judge makes a ruling affecting the materials that the special master can review, the review will continue on a parallel track.

Prosecutors wrote in Friday's filing that there was no claim for the return of the records that belonged to the government.

The parties were invited for a preliminary hearing by Dearie.

Larry Pfieffer, who led the White House situation room under George Bush, said that the decision not to separate the classified material shows a lack of deference by the judiciary to the executive.

In the past, Dearie attained a high level of security clearance and reviewed classified material, according to Insider.

It's not certain which security clearance Dearie will need for this review and how long it will take to get those authorizations.