Another day, another potentially illegal leak from special counsel Robert Mueller’s grand jury investigating Russian election meddling.

NBC News reported Monday that Mueller has “gathered enough evidence” to indict former national security adviser Michael Flynn and his son.

This followed the earlier leak to CNN — 72 hours in advance — that the grand jury had voted the first indictments in the investigation , later identified as former campaign chairman Paul Manafort and his business associate Rick Gates

And that raises the suspicion that the special counsel may be playing politics with his prosecutions.

True, the leaks may not necessarily have come from Mueller’s office, though the incentive for anyone else is pretty limited. (CNN identified its sources as people “briefed on the matter” and NBC as “sources familiar with the investigation.”)

Yet if the leaks did emanate from Mueller’s office or the grand jury itself, it would be a criminal violation.

And if Mueller is upset about the violations of grand jury secrecy, he hasn’t said anything about it publicly.

Rep. Trey Gowdy (R-SC), chairman of the House Committee on Oversight and Government Reform, says he specifically warned Mueller about “the importance of cutting out the leaks.”

Indeed, he added on “Fox News Sunday,” “it’s kind of ironic that the people charged with investigating the law and the violations of the law would violate the law.”

Actually, it’s more than ironic. It raises serious questions about the integrity and impartiality of the whole investigation.

Mueller, after all, has been criticized for staffing his probe overwhelmingly with prosecutors who are Democratic contributors.

As Gov. Chris Christie (a former US attorney) notes, with the stakes so huge, the public needs to “have confidence in the fact that the grand jury process is secret and, as a result, fair.”

Which puts the ball in Mueller’s court.