Convicted felon Frederick Celani’s history is a long, complicated tale — one in which the con man has claimed to work for the FBI and a House investigative subcommittee, and now stands charged with mail fraud for an alleged Ponzi scheme. But the latest chapter, the one in which he’s subpoenaed Rep. John Dingell (D-Mich.) to appear in federal court, should be relatively short.

The Michigan lawmaker, and dean of the House, has said no.

Specifically, the House Office of the General Counsel rejected the demand on Dingell’s behalf, calling for the subpoena to be dropped.

“We respectfully suggest that it is very doubtful that a defendant in a criminal fraud case would want to call as a witness or compel documents from a very distinguished American, who is the longest-serving Congressman in the history of the nation, who long ago labeled in a published report, with substantial proof, your client as a fraud artist,” House Assistant General Counsel Katherine McCarron wrote in a March 10 letter to Celani’s attorney.

The subpoena is one of more than two dozen issued to Members, staffers and House officers to date in the 111th Congress.

Notably, the subpoena issued to Dingell is accompanied by one of the more colorful backstories: Years after a 1986 meeting with Energy and Commerce Subcommittee on Oversight and Investigation aides about assertions that he knew of espionage related to a top-secret military project, Celani would claim to have received immunity from the panel, as well as cash and directions to stir up the 1992 Los Angeles riots. That prompted the subcommittee to issue a staff report in 1993 rebutting Celani’s claims.

But many of the subpoenas received by House offices are part of common civil lawsuits, and sometimes criminal cases.

Under House rules, Members, aides and officers are required to notify the Speaker’s office when they receive a subpoena or other judicial order, and the House Office of the General Counsel, which represents and gives legal advice to the chamber, advises those individuals on how to respond.

“When subpoenas are received by staffers or by Members they generally come to us and we provide advice,” explained General Counsel Irv Nathan.

The subpoenas make up only a fraction of the office’s workload, which also includes defending the constitutionality of federal statutes, enforcing subpoenas issued by Congress and its committees, and filing friend of the court briefs defending Congressional interests.

“It’s a minority of our time but it’s not an insignificant amount,” Nathan said.

“We represent them in seeking to obtain appropriate relief from the subpoenas,” he added, noting that when testimony or documents would violate the Constitution’s Speech or Debate Clause, which protects Members from prosecution for actions related to their legislative duties, the office will request a subpoena be withdrawn or ask the court to nullify it.

“We file motions in court to quash the subpoenas to the extent that they are seeking privileged information. We’re generally successful,” he added.

Typically, the office’s attorneys communicate through letters or court filings, but rarely do they appear in court, Nathan said.

Although those subpoenas are listed in the Congressional Record, current and former House counsels acknowledge such requests often receive little public attention.

“Casework produces demands for evidence more often than people realize because caseworkers are often asked for help in disputes,” said Charles Tiefer, a professor at the University of Baltimore School of Law who has previously served in both the House and Senate general counsel’s offices.

Such cases often occur in civil court, may include child support or immigration-related issues, and often include Social Security or veterans’ benefits.

Rep. John Sarbanes (D-Md.) received a subpoena in December to produce written communications his office exchanged with a constituent who filed suit in the U.S. District Court for the District of Maryland against American Express and several credit reporting agencies, asserting violations of the Fair Credit Reporting Act and other statutes after alleged fraud at her former employer negatively impacted her personal credit.

“There’s somewhere between a drizzle and a downpour of subpoenas,” Tiefer said. “Mostly in civil cases, but much less often in criminal cases, that comes to the House.”

In the current Congress, at least four House aides have been subpoenaed for testimony in cases in which an individual has threatened or harassed a Member’s office.

Aides to Rep. Bobby Scott (D-Va.) were sought to testify over a threatening letter their House office received, while aides to Rep. Tim Ryan (D) were called to testify in a case in which a man had harassed his Ohio office. According to the Youngstown (Ohio) Municipal Court, the suspect pleaded guilty but has yet to be sentenced.

Former aides to ex-Rep. William Jefferson (D-La.) were also subpoenaed in 2009 — the former lawmaker was convicted in August of 11 counts of public corruption and sentenced to 13 years in prison, and is now appealing the verdict — as was Justin Cox, a physician in the Office of the Attending Physician, who ultimately testified at the trial.

Members themselves were called to testify or provide documents in matters before state agencies, including Rep. Tim Holden (D-Pa.) and the Pennsylvania Environmental Hearing Board and Rep. Jean Schmidt (R-Ohio) and the Ohio Elections Commission.

Rep. Carolyn Cheeks Kilpatrick (D-Mich.) and a top aide were recently subpoenaed for testimony before a federal grand jury in Michigan. It is not clear what the investigation is focused on, but Kilpatrick has said neither she nor her aide are the subjects.

Former House counsels, including Tiefer, note that it is rare for a defense attorney or prosecutor to contact the office before issuing a subpoena to a Member or their staff.

“I wish they contacted the House Counsel’s Office more often, among other reasons, sometimes working out some alternative to the subpoena saves a lot of effort all around,” Tiefer said. Those alternatives, he explained, could include providing documents, such as House reports.

“Sometimes subpoenas seeking live testimony can be resolved simply by providing documents,” he added.

Defense attorney Stan Brand, who served as the first House general counsel beginning in 1979, established the office’s policies at a time when Members and aides had previously been represented by the Justice Department in official matters.

“I took a very expansive view of what we should be doing,” Brand said. “Anything that was officially related or impacted the institutional aspect of the House or its Members, I would make a case for,” he said.

Recalling the protocol under which Members and staff sought representation from DOJ attorneys, Brand said: “It was done as an accommodation.”

“The quality of representation was uneven,” he said. “We tried to provide a more consistent representation than they could get from the Justice Department.”