Clinton’s campaign, most Democrats and even some Republicans excoriated Comey for re-injecting the emails into the forefront of the presidential race. More than three months earlier, Comey said his agents had completed their investigation into whether Clinton mishandled sensitive government information and concluded that they did not have enough evidence to recommend charges.

“When this was investigated thoroughly the last time, the conclusion of the FBI, the conclusion of the Justice Department, the conclusion of repeated congressional investigations was that she had made some mistakes but that there wasn’t anything there that was prosecutable,” Obama said.

Others said Comey, who notified lawmakers of the new review in a brief letter Friday, should have released more information about it once he decided to go public. Senator Charles E. Grassley, the Republican head of the Senate Judiciary Committee, demanded that the director release more about the probe and complained that much of what was publicly known came from media reports.

Comey has agreed not to seek subpoenas or take other investigative steps in probes related to either Clinton or Donald Trump so close to the presidential election, a federal law enforcement official confirmed. That applies to an investigation involving the Clinton Foundation charitable organisation and another into whether Trump’s former campaign chairman, Paul Manafort, had improper business dealings with Ukraine.

Justice Department officials worried that taking public investigative steps could affect the outcome of the November elections, and Comey agreed with that determination in both cases, as first reported by The New York Times. Such actions would also have violated longstanding agency guidelines prohibiting law enforcement action or public statements about investigations within weeks of an election.

The new FBI probe comes at a critical moment not only for Clinton but also for Obama, who is focused intently on electing her to succeed him in the Oval Office.

With his legacy hanging in the balance, he has been on the campaign trail nearly every day this week on behalf of the Clinton campaign, telling voters that all of the achievements of his term in office could be wiped away if he is succeeded by Trump. He plans to travel at least three more days before the election.

And in interviews, Obama is trying to reassure voters who have concerns about the transparency of a Clinton administration. The news that the FBI may once again be looking at her use of a personal email server has given new life to concerns about whether she would comply with principles of openness and transparency if she were president.

Clinton campaign officials say they’re not worried about the effect of the Comey announcement on the electorate.

“If we’ve seen any impact from Jim Comey’s letter, it is to be a motivating factor for our supporters,” senior advisor Jennifer Palmieri said Wednesday. She said the campaign has set records for fundraising in the past few days.

At the same time, Democrats argue, Comey’s announcement raises concerns that may be baseless. It’s only right that Obama should call it into question, said Representative Adam Schiff, ranking Democrat member of the House Permanent Select Committee on Intelligence.

“It’s a subtle way for the president to say that the Department of Justice policies are sound and ought to be followed,” said Schiff. “I don’t think he was trying to be overtly critical of the director. … I don’t feel anyone in the administration thinks this was a good call. The view of the attorney general and other top lawyers in the Department of Justice is broadly shared in the administration.”

White House spokesman Eric Schultz argued that Obama’s remarks did not reflect any change in White House position.

“We do take seriously the longstanding norms and customs” that have historically limited what law enforcement can say about a pending investigation, Schultz said.

Those norms are designed to limit “speculation — and yes, innuendo,” he said.