Well, it is no secret that the President and his closest officials thought it was a terrible idea for their closest ally to leave the European Union. Their analysis was this: Bad for Washington; disastrous for British influence.
Now they're digesting the appointment of Boris Johnson as the man who will lead the UK's global diplomacy.
To put it politely, it has not gone down well. Don't even listen to the State Department spokesman saying it is business as usual.
The President's foreign policy team read and was deeply offended by the Boris article that talked of Barack Obama as "incoherent, inconsistent and downright hypocritical...a part-Kenyan President."
You can say it doesn't much matter. President Obama has only six months left in office. But I don't think that Mrs Clinton will view him differently.
One veteran Obama official put it this way: Brexit has diminished Britain in this town. Germany is now going to be more central to US policy in Europe. That is doubly true with the Boris appointment.
So let's just say this. Boris may want to start out with an apology to the occupant of the Oval Office.
Or he can hope Donald Trump wins in November. Then it won't matter. Oh hold on, Boris also said, "The only reason I wouldn't go to some parts of New York is the real risk of meeting Donald Trump."