Washington has a new parlour game: Just who was responsible for writing an extraordinary account of how senior Trump administration officials are working to protect the president from himself, and the world from an "amoral" commander in chief?
The article appeared as a rare unsigned piece in The New York Times, which described the author as "a senior official in the Trump administration whose identity is known to us and whose job would be jeopardised by its disclosure".
The result is a fresh wave of presidential anger, a White House hunt for the mole and widespread speculation about the source.
Several bookmakers are now offering odds.
These are the runners and riders, according to the Canadian online betting side Bovada.
Jeff Sessions, Justice Secretary, 5/2
A frequent target of the president’s wrath and his department faces constant pressure to act as Mr Trump’s personal defence team. He has had to tread a fine line in carrying out the president’s wishes while staying on the right side of the law.
Mike Pence, Vice-President, 3/1
The Vice President puts his name on his Op-Eds. The @nytimes should be ashamed and so should the person who wrote the false, illogical, and gutless op-ed. Our office is above such amateur acts.
— Jarrod Agen (@VPComDir) September 6, 2018
Installed as an early favourite when online sleuths pointed out the op-ed piece used the word “lodestar”, a mainstay of his speeches. However, he is known for quiet, loyal service to the president and his office on Thursday denied that he was the author.
John Kelly, White House Chief of Staff, 4/1
The former Marine general was appointed to the West Wing to bring order to a chaotic White House. However, it is no secret that he has struggled to impose a chain of command and frequent leaks suggest impatience with the president.
Nikki Haley, Permanent Representative to the UN, 10/1
A favourite of Mr Trump but also viewed as ambitious, with her eye on higher office. The op-ed draws examples from foreign relations, fuelling speculation the author is drawn from the national security of foreign policy spheres
Javanka, senior counsellors, 15/1
Ivanka Trump and her husband Jared Kushner are often portrayed as the liberal, internationalist voice of reason within the inner circle. But would Ivanka ever move so publicly against her own father?
Don McGahn, White House counsel, 15/1
The lawyer is planning to leave the White House later this year so has little to lose. He has clashed privately with Mr Trump, notably over an order to fire Robert Mueller as special counsel leading the Russia investigation.
Donald Trump, President, 25/1
Maybe it’s just a joke. Then again, Mr Trump used to pose as his own spokesman, John Barron, in calls with reporters back in his New York days. And could the op-ed stir up his base against Washington’s dark, swampy forces?