(Stefan Rousseau/Reuters)

Even as the FBI said Tuesday that it would not recommend charging Hillary Clinton for putting her work email on a private server when she was secretary of state, a federal court may have just opened the door to more scrutiny of the Democratic presidential candidate.

The facts of the court ruling -- in the case of another government official -- have little to do with Clinton herself. But the decision from the U.S. Court of Appeals for the D.C. Circuit appears to hold significant  implications for the presumptive Democratic nominee as she seeks to deflect attention away from her online records and focus her energy on Republican rival Donald Trump.

The D.C. Circuit held in its decision that work email stored privately is still subject to Freedom of Information Act requests. The whole point of FOIA, the court said, is to provide transparency on public officials' behavior while in office. Circumventing that by hosting government documents on non-governmental servers defeats that purpose, Judge David Sentelle said.

In other words, work emails are work emails, no matter where they happen to live or who happens to control access to them.

"It would make as much sense to say that the department head could deprive requestors of hard-copy documents by leaving them in a file at his daughter’s house and then claiming that they are under her control," Sentelle wrote.

Judge Sri Srinivasan wrote a separate opinion in which he used an analogy to files in the physical world. The government, he said, can't simply "bury its head in the sand" and not produce a FOIA-requested document just because an employee took it home with her that night. It would still be out there, and the agency would still be responsible for it — although it could decide on other grounds not to release it to the public, as agencies often do.

The case had to do with the private email account belonging to an official who works for the Office of Science and Technology Policy, a branch of the White House. Yet the ruling makes its possible that FOIA requests for Clinton's work emails could cover not only the ones stored in her government email account, but also those stored privately.

Last month, a federal judge put a temporary hold on a lawsuit related to Clinton's privately held emails, saying it would be "wise" to wait for the D.C. Circuit to issue its FOIA ruling before moving ahead with the suit. It's unclear how that lawsuit may turn out, but the judge appeared to show deference to the D.C. Circuit's eventual decision.

The D.C. Circuit's ruling that private email accounts can be subjected to FOIA requests could put greater pressure on Clinton from conservatives seeking to make the candidate's emails an election-defining issue.