Special counsel Robert S. Mueller III. (Michael Reynolds/European Pressphoto Agency/Shutterstock)

“MY PEOPLE were very upset about it,” President Trump said Sunday of emails obtained by special counsel Robert S. Mueller III belonging to the presidential transition team. Yet despite much arm-waving, Mr. Trump’s “people” have provided no evidence supporting their claims of misconduct by Mr. Mueller. This feigned outrage over the special counsel’s search of transition-team emails is just one more attempt by Mr. Trump’s allies to kick up dust around Mr. Mueller’s investigation.

The latest diversion began with a letter to Congress from Mr. Trump’s transition team alleging that Mr. Mueller had improperly obtained emails belonging to transition members. According to the letter, Mr. Mueller’s investigators requested transition emails and devices from the General Services Administration (GSA), the agency that provided the transition team with laptops and cellphones and hosted their government emails. Even though the transition used .gov email accounts, the letter argues, GSA General Counsel Richard Beckler agreed after the inauguration to treat the accounts as private. Yet the GSA handed the documents over to Mr. Mueller at his request.

This might be concerning — if it were the full story. But GSA Deputy General Counsel Lenny Loewentritt, who the transition claims was present when Mr. Beckler agreed that the emails would be treated as private, says that Mr. Beckler made no such promise. Mr. Loewentritt points instead to documents in which transition officials signed away their expectation of privacy in order to use GSA systems and devices. (Mr. Beckler has since died.) So the transition team likely had no basis to expect that the GSA would shield correspondence from the special counsel. In a rare public statement, Mr. Mueller’s spokesman Peter Carr declared, “When we have obtained emails in the course of our ongoing criminal investigation, we have secured either the account owner’s consent or appropriate criminal process.”

The transition team also argues that Mr. Mueller should have filtered out emails protected by executive privilege and attorney-client privilege, both of which can shield communications from being used against a defendant. But the former privilege applies only to the executive branch — and the transition team is claiming it should be treated as a private entity. And while some emails could conceivably contain privileged advice from lawyer to client, the letter describes no improper behavior by the special counsel. If Mr. Mueller seeks to use privileged materials in legal proceedings, transition members can always challenge him in court. Or they could act now by bringing the matter before the federal judge overseeing Mr. Mueller’s grand jury.

The fact that the Trump team has chosen instead to air its grievances before two congressional committees with no jurisdiction over Mr. Mueller suggests this letter is little more than a political stunt. As with last week’s release of anti-Trump text messages by an FBI agent who had been detailed to the special counsel, Mr. Trump’s allies are desperate for any shred of an excuse to cast doubt on Mr. Mueller’s investigation. Their wisest course would be to trust in the special counsel’s integrity and let him do his work.