This may leave you asking: What have these people done to merit a presidential pardon?

Mr. Black, whose pardon the White House announced late on Wednesday , had the backing of Rush Limbaugh and Henry Kissinger, among others. But the erstwhile media mogul, who was convicted of fraud and obstruction of justice and served more than three years in federal prison, may have made the best case for himself by writing a hagiography, “Donald J. Trump: A President Like No Other,” which contained no shortage of praise for its subject.

Mr. Nolan, for his part, was implicated in what The Los Angeles Times called “one of Sacramento’s most notorious political corruption cases,” for which he served 26 months in prison. Mr. Nolan received an assist from The American Spectator, a right-leaning publication, which last year published an article that urged Mr. Trump to pardon him. The Spectator’s argument suggested that Mr. Nolan merited a pardon because he was, in the eyes of the writer, wrongly convicted and because of his work as a longtime advocate for criminal justice reform. It went on to echo Mr. Nolan’s previous remarks, calling the Mueller investigation a “promiscuous witch hunt” and accusing officials at the Justice Department of improprieties.

It’s a pattern seen in the pardons for Joe Arpaio, the Arizona sheriff and ardent Trump supporter who was convicted of criminal contempt for refusing to comply with a court order to obey the Constitution; Dinesh D’Souza, the provocateur who was convicted of campaign finance violations by the office of Preet Bharara, the United State attorney in New York whom Mr. Trump unceremoniously fired and Mr. D’Souza has accused of selective prosecution; and Scooter Libby, a former aide of Vice President Dick Cheney convicted of perjury and obstruction related to the outing of a C.I.A. officer.

In these and other cases, claims of injustice, unfairness and overreach by the Justice Department have driven the calls for mercy. Powerful intermediaries, such as elected officials, have pressed the issue with the president. On one occasion, the invocation of the Hillary Clinton email scandal on “Fox & Friends” seemed to have sealed the deal for one of the pardoned, Kristian Saucier, whose case the president had already championed during the 2016 campaign.

The way Mr. Trump has invoked his pardon authority has not gone without scrutiny. In his obstruction of justice investigation of the president, Robert Mueller, the special counsel, examined numerous episodes where the prospect of a presidential pardon appeared designed to influence the conduct of witnesses or associates of the president, such as Paul Manafort and Michael Cohen.