McGahn responded to Trump’s request by writing a memo to the president outlining the consequences that he’d face if he pushed the traditionally independent Justice Department to investigate a political rival, the New York Times reported.
The consequences included the Justice Department refusing to comply as well as public outcry and congressional probes that could culminate in Congress beginning impeachment proceedings over potential abuse of power.
Trump raised the matter with McGahn on numerous occasions, according to CNN.
McGahn, who has reportedly been cooperating extensively with special counsel Robert Mueller’s investigation into Russian election meddling and collusion with the Trump campaign, departed his position as White House counsel in October.
WATCH: Trump calls Don McGahn a ‘good guy’ after announcing departure from White House
It wasn’t clear what charges Trump wanted the Justice Department to pursue against Clinton, although he has repeatedly assailed the former Democratic presidential candidate over her use of a private email server during her tenure as secretary of state, as well as her role in the Obama administration’s move to let a Russian company buy a uranium mining firm.
The New York Times reported that Trump’s lawyers also asked Justice Department prosecutors to probe former FBI director James Comey over his role in the Clinton email investigation, and that law enforcement officials refused those requests.
Comey is a witness for the prosecution in special counsel Robert Mueller’s investigation into possible collusion between the Trump campaign and Russian officials
The White House and the Justice Department did not immediately respond to a request for comment.
— With files from Reuters