President Trump has angrily denied claims that his former lawyer, Michael Cohen, is willing to testify that Mr Trump knew and approved of the 2016 meeting between his son Donald Jr. and Russian government officials.
The meeting saw the Trump campaign offered “very high level and sensitive information” as part of “Russia and its government’s support for Mr Trump”.
The president regularly insists he did not know of the meeting.
If true, this revelation would directly implicate Mr Trump himself in an effort to conspire with a foreign power to tip the election to him, and a subsequent cover-up effort.
US commentators are saying the importance of this story may not lie in what Cohen is willing to say about Trump’s alleged knowledge of this meeting.
Rather, the further unravelling of the Cohen-Trump relationship could lead Mr Cohen to share previously undisclosed information about other matters related to Mr Trump’s relationship with Russia that are still shrouded in mystery.
Mr Cohen alleges that he was present, along with several others, when Mr Trump was informed of the Russians’ offer by Trump Jr.
According to Mr Cohen’s account, it was Mr Trump who approved proceeding with the Russian meeting.
But it must be remembered that Mr Cohen is a disgruntled ex-employee of Mr Trump’s. He may have a score to settle.
Mr Trump’s present lawyer, Rudy Giuliani, says the version of events that are supposedly about to be put forward by Mr Cohen never happened.
The testimony of Mr Cohen could also prove useful in answering other areas of interest identified by Robert Mueller’s inquiry.
Special Counsel Mueller allegedly has evidence that Mr Cohen secretly travelled to Prague in the summer of 2016 to discuss concealment strategies with Russian officials over the extent of his then-employer’s links to Moscow.