A sprawling lawsuit against the former mayor of New York and attorney for President Trump, Rudolph Giuliani, alleges that he was selling pardons by the president in the latter months of Mr. Trump’s term. Legal analysts, though, say such charges may be hard to prove.

Among a long list of allegations against Mr. Giuliani, his former employee who brought the case, Noelle Dunphy, alleges that Mr. Giuliani was selling pardons for profit.

The complaint describes Mr. Giuliani asking Ms. Dunphy “if she knew anyone in need of a pardon, telling her that he was selling pardons for $2 million, which he and President Trump would split.”

“He told Ms. Dunphy that she could refer individuals seeking pardons to him, so long as they did not go through ‘the normal channels’ of the Office of the Pardon Attorney, because correspondence going to that office would be subject to disclosure under the Freedom of Information Act,” the complaint alleges.

Mr. Giuliani “unequivocally denies the allegations raised by Ms. Dunphy,” according to a statement from his communications advisor, Ted Goodman.

“Mayor Giuliani’s lifetime of public service speaks for itself and he will pursue all available remedies and counterclaims.,” he said in the statement.

While it will be up to the court or a jury to decide the veracity of Ms. Dunphy’s claims, this isn’t the first time that Mr. Trump’s presidential pardons have come under scrutiny.

Mr. Trump pardoned more than 143 people, some of whom had only tangential ties to the president. The new complaint raises the question of whether any of those people paid a price for those pardons.

Some individuals, like rapper Dwayne Michael Carter Jr., better known as Lil Wayne, or rapper Bill Kahan Kapri, better known as Kodak Black, raised eyebrows at the time. Mr. Trump also pardoned some prominent conservatives, like commentator Dinesh D’Souza and the ex-husband of “The Five” host, Al Pirro.

According to the vice president of the New York County Lawyers Association, Richard Swanson, allegations of pardon selling, even if true, may be hard to prove in court due to recent changes in the application of federal law.

“The Supreme Court has been restricting the federal application of mail fraud and wire fraud statutes in public corruption cases, including Bridget Kelly in ‘Bridgegate’ and last week’s Percoco decision,” Mr. Swanson said. “So it may be more difficult to prosecute a case for selling pardons than people expect.”

Ms. Kelly was the deputy chief of staff to Governor Christie of New Jersey, and was convicted of fraud, conspiracy, and depriving the residents of Fort Lee, New Jersey, of their civil rights in November 2016.

In 2020, the Supreme Court delivered a rare unanimous decision to overturn her fraud conviction, writing that “not every corrupt act by state or local officials is a federal crime.”

“Because the scheme here did not aim to obtain money or property, Baroni and Kelly could not have violated the federal-program fraud or wire fraud laws,” Justice Elena Kagan wrote in the opinion.

Last week, the Supreme Court further chipped away at a prosecutor’s ability to use fraud statutes to prosecute corruption in a case concerning a one-time top aide to Governor Cuomo, Joseph Percoco.

In the case, the court once again ruled unanimously against upholding a conviction in federal court for the Southern District of New York for honest services fraud, or defrauding another of the right to honest services in a fiduciary context. The Nine ruled that jurors in the Southern District had been given “erroneous” instructions on what constitutes fraud.

“The jury instructions did not define ‘the intangible right of honest services’ with sufficient definiteness that ordinary people can understand what conduct is prohibited,” Justice Samuel Alito wrote in the court’s opinion.

In short, Mr. Swanson argues that, even if Mr. Giuliani did tell Ms. Dunphy that he was selling pardons, that doesn’t mean he did so in an explicitly illegal way. One could imagine a scheme involving campaign donations that circumvents legal statutes and campaign regulations, he said.

“Rudy Giuliani’s life appears to have gone off the rails so I take any statements he makes in any context these days with a large grain of salt and I think as a result the statements may not reflect the full state of facts at a minimum and may not be credible at all and therefore we have to await further investigation and fact gathering,” Mr. Swanson said.