If the Supreme Court just sent a message about prosecutorial overreaching, US Attorney Carmen Ortiz was unfazed by it.

She isn’t backing down from another high-profile prosecution, aimed directly at the administration of Boston Mayor Martin J. Walsh. On Wednesday, Ortiz’s office charged Timothy Sullivan, the acting director of the city’s office of Intergovernmental Relations, with extortion and conspiracy. This follows an earlier indictment of Kenneth Brissette — Walsh’s director of tourism, sports, and entertainment — on similar charges.

The two aides are accused of forcing a production company to hire union workers for the Boston Calling music festival on City Hall Plaza. The charges were brought under the federal Hobbs Act, which requires prosecutors to show the defendant induced, or attempted to induce, the victim to give up property or property rights by threatening physical injury or economic harm.

Just this week, the Supreme Court reversed the conviction of a former Virginia governor, Bob McDonnell, on extortion charges that also were filed under the Hobbs Act, as well as his conviction on charges of “honest services fraud.’’ The facts are quite different from those involving the two Walsh aides. But defense lawyers interpreted the ruling in McDonnell v. United States as a general warning to prosecutors to think twice about making a federal crime out of unpleasant but lawful “business as usual.’’

Unpleasant but lawful conduct will be the argument in defense of Walsh’s aides. According to Wednesday’s indictment, festival organizers hired eight union laborers and one foreman because Sullivan and Brissette insisted upon it. It will be up to federal prosecutors to show that the effort by Sullivan and Brissette to persuade or pressure constitutes unlawful “extortion,’’ or, conversely, for the defense to show it actually was “permissible, maybe even fairly common contact,’’ said noted criminal defense lawyer Harvey Silverglate.

Ortiz has won that argument before.

Since taking over in 2009, she has overseen the successful prosecution of three well-known politicians — former state senator Dianne Wilkerson, Boston City Councilor Charles Turner, and former House Speaker Salvatore F. DiMasi. The prosecutions of James “Whitey’’ Bulger and Boston Marathon bomber Dzhokhar Tsarnaev, which also happened on her watch, drew international attention. If the attention has not always been positive, that goes with the prosecutorial turf.

In 2013, Ortiz was on the hot seat for prosecuting Aaron Swartz, a 26-year-old Internet activist who committed suicide after federal prosecutors targeted him for using computers at MIT to gain access to scholarly papers. A circle of powerful friends took up Swartz’s cause, arguing that overzealous prosecution led to his death. A petition calling for Ortiz’s removal reached the threshold of 25,000 signatures required for a White House response. Ultimately, however, President Obama declined to rule on it.

In 2014, a political corruption case targeting three employees of the state probation department also called Ortiz’s judgment into question. Federal prosecutors argued — and a jury agreed — that a rigged hiring system set up by probation chief John “Jack’’ O’Brien amounted to a criminal enterprise. House Speaker Robert DeLeo was tied to the hiring scheme by a veteran prosecutor, but never indicted, and Ortiz was criticized for allowing her office to call him a coconspirator without bringing charges. DeLeo denied any wrongdoing.

O’Brien’s conviction rocked Beacon Hill, and colleagues said that what he did was not a crime. Indeed, Walsh himself defended O’Brien on a radio show in July 2014, saying, “He went to work every day to do his job. I think somehow the system got the better of him.’’ When those remarks generated headlines, Walsh issued a statement calling O’Brien “a good man,’’ and explaining that elected officials “have an obligation to be helpful to their constituents, including — when appropriate — assistance with employment opportunities, writing letters of recommendation for schools, and so on.’’

From that perspective, Walsh’s two aides were simply helping labor union constituents get assistance with employment. Is that a crime? Ortiz stands ready to make that case, and history shows she knows how to win it.

Joan Vennochi can be reached at vennochi@globe.com. Follow her on Twitter @Joan_Vennochi.