A veritable who's who of Pennsylvania politics could end up taking the stand when U.S. Rep. Chaka Fattah goes on trial next year on federal racketeering conspiracy charges.

A list of possible government witnesses filed with the court Tuesday contains such boldface names as U.S. Sen. Robert P. Casey (D., Pa.), former Gov. Ed Rendell, and State Sen. Vincent Hughes (D., Phila.).

Also mentioned are behind-the-scenes political players, including Greg Harvey, a veteran Philadelphia election lawyer, and William Sasso, a prominent GOP donor, a confidant of former Gov. Tom Corbett, and chairman of the law firm Stradley Ronon.

Even a Democratic congressman from Florida, Rep. Ted Deutch, rates a spot, for reasons not yet clear.

Some, including Harvey, said they were not surprised to hear of their names being listed in court filings. He testified before a grand jury about a debt Fattah's 2007 mayoral campaign owed his law firm.

Others, such as Sasso, said they had no idea what they might add to the government's case against Fattah. "I can't imagine anyone's calling me for anything," he said. "It doesn't make any sense."

Lawyers for Fattah revealed the list of 22 names out of a total of 122 on Tuesday as they sought permission for the congressman to stay in touch with the people on it as he prepares for a May 2 trial date.

Last week, a federal judge barred the Democrat, who represents a large portion of Philadelphia and a small section of eastern Montgomery County, from contacting any of the government's 122 potential witnesses except those currently working in his office.

But lawyer Kevin V. Mincey argued Tuesday that his client routinely seeks counsel from several people on the Justice Department's list and needs to maintain contact with them to effectively do his job.

"The government's proposal that Mr. Fattah only be allowed to speak to persons identified as potential witnesses who are currently under his employ does not take into consideration how often the congressman consults with individuals who are not on his current staff," the lawyer wrote in Tuesday's motion. "On a near-daily basis, engaging such individuals - some former staffers - may be required to address representative matters."

Fattah, 58, has repeatedly denied taking bribes or using federal grant money, campaign funds, and charitable donations he controlled to pay off debts and line the pockets of his family and inner circle.

Some people on Tuesday's list have clear connections to the allegations lodged against Fattah.

For instance, Casey and Ron Kirk, U.S. trade representative between 2008 and 2013, appear to be alluded to in the government's 29-count indictment.

Prosecutors say Fattah approached several officials between 2008 and 2011 as he sought various appointments in the Obama White House for Herbert Vederman, a well-connected Philadelphia lobbyist accused of bribing the congressman. Vederman, the government asserts, was seeking appointments as ambassador or trade representative.

John Rizzo, a spokesman for Casey, said Tuesday that the senator received a letter from Fattah in 2008 on behalf of Vederman, and passed Vederman's name on to the White House. Vederman was one of more than 200 Pennsylvanians whom Casey directed to the administration, the spokesman said.

"Other than his inclusion on that list, Sen. Casey's office did not advocate for or otherwise help Mr. Vederman," Rizzo said.

Kirk declined to comment.

Hughes, too, was cited - though not by name - in connection with another alleged scheme.

While trying to hide what prosecutors have described as another Vederman bribe in 2012, Fattah arranged a fake sale to the lobbyist of his wife's 1989 Porsche Carrera, they have charged. The congressman turned to Hughes' office for help in obtaining a duplicate title for the car, according to the indictment.

Others named as potential witnesses include several former Fattah staffers, including Maisha Leek, his former chief of staff, and Nuku Ofori, the ex-legislative director for a House Appropriations subcommittee Fattah once led.

The list also cites a handful of former employees of nonprofit groups Fattah supported for years through congressional earmarks. One of them, James P. Baker Jr., ran the Caribbean-American Mission for Research, Education and Action, a charity that spent more than $2 million in federal funds on environmental education and other projects. The charity also sent groups of Philadelphia high school students to a luxury resort in the U.S. Virgin Islands.

Others on the government's witness list have ties to Fattah's failed 2007 bid for Philadelphia mayor, a campaign prosecutors say accepted a $1 million illegal loan and paid it back with a mix of misappropriated federal and charitable funds.

Harvey, the election lawyer, represented Fattah during an attempt that year to overturn the city's $2,500 campaign finance cap in court.

In an interview Tuesday, he said he testified more recently before a federal grand jury about the debt Fattah's campaign owed his law firm for work on the case. The firm forgave a portion of that debt in 2008, Harvey said, in a deal negotiated by Vederman, who claimed the campaign was unable to pay.

Prosecutors now allege that even as Fattah's campaign was claiming financial duress, it was paying thousands of dollars to cover the student loans of the congressman's son, Chaka "Chip" Jr.

"The government's theory is that I and the law firm were defrauded because Vederman said that there was not sufficient money in the campaign account to pay their bill," Harvey said.

Yet some on the list were left scratching their heads for any relevant connection.

Reached Tuesday, Sasso, the Republican donor, was at a loss to explain why he had been named as a potential government witness or why Fattah's lawyers would describe him in court filings as a "close political adviser."

His firm, Stradley Ronon, employed both Vederman and another man on the government's list, John Saler. But when federal authorities contacted him months ago, he said, they asked only about a fund-raiser he hosted for Fattah several years ago at Rendell's request.

Other than that, said Sasso, his contact with the congressman was limited to infrequent calls about what federal resources might be available to various education nonprofits represented by his firm.

"If called upon to be a character witness," he said. "I'd say he always tried to be helpful in providing information."

jroebuck@phillynews.com215-854-2608@jeremyrroebuck

Inquirer staff writer Chris Brennan contributed to this article.