Tom Petters returns to federal courtroom 7A in St. Paul this week in an attempt to shorten his prison sentence by 20 years. With all other appeals exhausted, this may be his last chance to shorten his 50-year prison stay.

Petters, 56, who resides at the federal penitentiary in Leavenworth, Kan., will take the stand on Wednesday in a hearing where the main witnesses against him will be the attorneys who defended him during his 2009 jury trial.

Petters was convicted in the same courtroom on Dec. 2, 2009, on 20 counts of fraud, conspiracy and money laundering for orchestrating a phony business operation that sold fictitious electronic goods to big-box retailers and used proceeds from new investors to pay off ­earlier investors.

At trial, he testified that his associates conducted the decadelong, $3.65 ­billion Ponzi scheme while he was distracted by the death of a son and other business obligations.

The jury didn’t buy it.

The issue at the heart of this week’s hearing is whether federal prosecutors offered Petters a plea bargain with a sentence capped at 30 years, whether attorneys for ­Petters relayed that offer to their ­client and whether he had the opportunity to accept it.

Petters’ defense team asserts that a 30-year plea deal was discussed with Petters on multiple occasions and that it was rejected by Petters each time as too onerous.

His sentencing appeal is built around the legal concept known as “ineffective assistance of counsel.” It asserts that his attorneys failed to inform him about the plea offer before trial.

Such claims are not uncommon, but generally have a low probability of success, legal authorities say.

“In order to succeed, a defendant has to show both that his counsel was ineffective and also that there is a reasonable probability that counsel’s mistake affected the outcome,” said Ted Sampsell-Jones, a criminal law professor at William Mitchell College of Law in St. Paul. “You have to show that your counsel did something that was objectively unreasonable — something so stupid that no reasonable criminal defense attorney would have made that decision. It is hard to do.”

Recent ruling could be key

Petters’ current attorney, Steven Meshbesher, believes that a 2012 ruling of the U.S. Supreme Court bodes well for Petters’ case.

In that ruling, the high court determined that a defense attorney did not act in his ­client’s best interest when he received a written plea agreement offer from prosecutors but did not present it to the defendant before it expired.

“This case makes it clear that any discussion between prosecutors and defense attorneys has to be relayed to the defendant,” Meshbesher said in an interview. “The defendant has to make the choice whether to accept it, not the lawyer.”

Christopher Madel, the attorney representing the Petters defense team in the sentencing appeal, said: “The motion is laughable that these incredibly accomplished attorneys would do what is alleged with this [allegation] coming from the most accomplished fraudster in ­Minnesota history.”

In its briefing papers filed with the presiding judge in the case, U.S. District Judge Richard Kyle, the U.S. attorney’s office insists that the Petters motion should be tossed out if he fails to prove that a formal plea offer existed and was not presented to him and that he “would have admitted his guilt and pleaded guilty” if given the opportunity.

Meshbesher asserts that Petters was unaware of the possible plea offer until after his conviction in late 2009.

“After the verdict was read and entered, he [Petters] was visited by Mr. [defense attorney Jon] Hopeman in the holding cell at which time Mr. Hopeman stated, ‘Well, we had to go to trial [because] we could only get you a 30-year minimum deal,” states Meshbesher’s brief to Kyle. Petters “affirms that prior to that he had never been informed of the government’s offer.”

Meshbesher called Petters’ 50-year sentence “disproportionately harsh” compared with other defendants in the case and said Petters told his defense team “on multiple occasions” that he would plead guilty in exchange for a five- to 20-year sentence.

In addition to Petters, his scheduled witnesses include one of his brothers and his two sisters, and Shauna ­Kieffer, an attorney who did the original research that laid the groundwork for the motion to allow Petters to accept the lesser sentence.

The original defense team is unanimous in its position that he was aware of the offer and that he insisted he was innocent throughout the case.

“For most of the time I represented Mr. Petters, he had little or no interest in pleading guilty to any crime,” Hopeman said in a court filing. “Mr. Petters said he had no interest in a deal that would require him to serve so much time.”

Hopeman said attempts to strike a deal with federal prosecutors for a sentence of fewer than 30 years were unsuccessful.

The attorney added that he felt 30 years was too harsh of a sentence and that he informed prosecutors that “my professional integrity would not allow me to recommend such an offer to Mr. Petters.”

In addition to Hopeman, the witnesses on behalf of the U.S. attorney’s office will be defense attorneys Paul Engh and Eric Riensche and private investigator William O’Keefe.