Donald Trump, the US president, wanted the justice department to prosecute his political opponents Hillary Clinton and James Comey, the New York Times has claimed, but had to be informed that pursuing a prosecution would be unwise.
Mr Trump raised the issue of prosecutions in the spring of this year, two sources told the paper.
It was not clear on what grounds he sought the prosecution, although he has repeatedly attacked Mrs Clinton for her private use of an email server for official government business, and led chants of "lock her up". He has accused Mr Comey of leaking classified information.
Donald McGahn, the then-White House counsel, informed Mr Trump that he had no authority to order a prosecution, and could only request an investigation.
He warned, however, that requesting an investigation could be deemed an abuse of power, and drew up a memo from White House lawyers explaining the problem with attacking Mrs Clinton and Mr Comey, the former FBI director.
The memo spelled out that were Mr Trump to investigate his rivals, he could face a range of consequences, including possible impeachment.
Mr McGahn, who left the White House in October after a tumultuous tenure, appeared to have dissuaded the president, but the paper reported that Mr Trump continued to privately discuss the matter, including the possible appointment of a second special counsel to investigate both Mrs Clinton and Mr Comey.
He also repeatedly expressed disappointment in the FBI director he appointed to replace Mr Comey, Christopher Wray, for failing to more aggressively investigate Mrs Clinton.
Mr McGahn’s lawyer, William Burck, said: “Mr McGahn will not comment on his legal advice to the president. Like any client, the president is entitled to confidentiality."
He added: "Mr McGahn would point out, though, that the president never, to his knowledge, ordered that anyone prosecute Hillary Clinton or James Comey.”