Almost from the moment former President Donald J. Trump was charged last June with mishandling a trove of highly secret classified documents, the spotlight in the case has been fixed — as it usually is — on him.

But on Friday afternoon, the focus will shift, at least briefly, to Mr. Trump’s two co-defendants, Walt Nauta and Carlos De Oliveira. Their lawyers will square off in court with federal prosecutors in an effort to have the charges they are facing dismissed.

Prosecutors say that both men — who still work for Mr. Trump at Mar-a-Lago, his private club and residence in Florida — conspired with the former president to hide boxes containing classified material from the government and then took part in a related plot to destroy security camera footage of the boxes being moved. The men have also been accused of lying to investigators.

In some sense, Mr. Nauta, a personal aide who met Mr. Trump while serving as a valet at the White House, and Mr. De Oliveira, who rose at Mar-a-Lago from parking cars to working as the property manager, are merely supporting players in the larger drama starring Mr. Trump.

But at the same time, they are central to the case because they both play leading roles in the allegations that Mr. Trump willfully conspired to obstruct the investigation. Those accusations have not only deepened Mr. Trump’s own criminal liability, but have also served to set his case apart from other inquiries into classified materials involving public officials like President Biden and former Vice President Mike Pence.