“It’s almost mission impossible here for a lot of different reasons,” said historian Chris Whipple. “His credibility was already really seriously damaged going all the way back to his appearance behind the podium in the WH briefing room. Now I think his credibility is really beyond repair and moreover, very few people will really believe he’s really speaking for the president.”

Kelly’s defenders agree he has an impossible task but say he has a clear-eyed view of the president he serves and does the job out of a sense of duty. With few real confidants inside the West Wing — and no principal deputy to help him run the White House — the retired Marine general finds himself increasingly isolated inside the West Wing.

Kelly was aware weeks before the Daily Mail story that Porter’s background check had turned up red flags — though not the full extent of the abuse — but Porter never rose to the top of his list of problems to deal with.