The revival of public corruption charges Thursday against two top City Hall aides poses challenges for both the federal prosecutor overseeing the case, and the mayor who has been dogged by it for most of his time in office.

US Attorney Andrew Lelling’s successful appeal of the dismissal of the initial charges last year shows he is determined to see the case through, legal and political analysts said. But the charges are now three years old, they noted, which requires Lelling to reassess the elements of the case, amid a new legal and political climate.

“The lapse of time can always be a factor. . . . One never knows how, over the passage of time, how that’s going to impact a case,” said Brad Bailey, a Boston lawyer and former prosecutor. He said prosecutors will have to look at the merits of the indictment, the availability of witnesses, and quality of evidence.

But, Bailey added, “I don’t think the government would have gone as far as they went if they didn’t want to pursue the case.”


Lelling’s office has not said whether it will try to bring the case to trial again.

The indictment charged Kenneth Brissette, Mayor Martin J. Walsh’s head of tourism, and Timothy Sullivan, head of intergovernmental affairs, with extortion for allegedly threatening to withhold city permits for the Boston Calling music festival in 2014 unless organizers hired union stagehands.

Brissette and Sullivan remain on staff, though they were on paid leave while the case had been pending in US District Court.

Prosecutors alleged that the concert organizer, Crash Line, was harmed by the demand because it ultimately hired eight union laborers and one foreman, even though it had already retained a nonunion company to perform the work.

But in 2018, prosecutors conceded the case after US District Judge Leo T. Sorokin’s ruled that his jury instructions would have required them to prove that Sullivan and Brissette personally benefited from the hiring of union workers. Prosecutors acknowledged they could not meet that standard if the case had gone to trial.


Instead, they appealed Sorokin’s jury instructions, arguing that they could prove extortion simply by showing that Brissette and Sullivan had an interest in having Crash Line hire union workers because it would support the political ambitions of Walsh, a former head of a union trade group who was elected with the help of labor support. The loss of the permits would have cost the company hundreds of thousands of dollars, according to court records.

The appeals court ruled Thursday that Sorokin misinterpreted the law, and sided with prosecutors.

Lelling was not the US attorney when the case was originally charged in 2016. But he pushed and defended the appeal of Sorokin’s decision.

Martin Weinberg, a Boston-based lawyer, pointed out that Lelling is also working in a new legal climate, in which the US Supreme Court has warned prosecutors against overreaching in cases involving decisions by public officials. He noted the appeals court called this case a “novel prosecution” of the theory of extortion under the Hobbs Act, a federal law often used in public corruption cases.

“This City Hall case. . . will test the proper boundaries of extortion law” . . . and “will again provide the court with an opportunity to find the boundaries for the criminal statute that the federal government looks to expand,” Weinberg said.


Scott Ferson, who runs the public affairs company Liberty Square Group, said Lelling’s decision could again cast a shadow over City Hall, although Walsh’s political position appears stronger with his resounding reelection in 2017 while the case was pending. Moreover, the charges have not prompted Walsh to retreat from his pro-union stances.

“It’s a good public policy to have: ‘I want elected officials who are going to champion union work,’ ” Ferson said. But, he added, “when there are indictments hanging over any mayoral office, you prefer not to have it.”

Milton J. Valencia can be reached at milton.valencia@globe.com.