WASHINGTON, D.C. – Imprisoned former Cuyahoga County Commissioner Jimmy Dimora has taken his case for a new trial to the U.S. Supreme Court.

Dimora asked the highest court in the country to reexamine and overturn a federal appeals court's denial of his request for a new trial on racketeering and 29 other corruption-related charges on which he was convicted in 2012.

Dimora, 58, is serving a 28-year sentence at a federal prison in Victorville, Calif.

"He's hopeful," said Dimora's appeals lawyer, Christian Grostic, this morning. "He doesn't believe he got a fair trial the first time, and he wants a chance to prove his case."

Grostic said he mailed a 74-page document to the Supreme Court known as a writ of certioari, which is a formal request to review his argument for a new trial. In order to succeed in his last-ditch appeal, four of the Supreme Court's nine justices must first agree to hear his arguments.

The Supreme Court is on summer break, so the earliest the justices will decide whether to hear the request would be when they reconvene for a conference Sept. 29, Grostic said. The justices could postpone their decision to a later date. The U.S. Solicitor General's Office also could file a brief on behalf of the prosecutors in the case, which might delay the case further, he said.

In his request to be heard by the justices, Grostic argued that U.S. District Court Judge Sara Lioi mistakenly denied Dimora's attempt at trial to present the best evidence of his innocence: his state ethics disclosure forms.

Dimora maintained that the disclosure forms would have shown that what prosecutors had called bribes that he attempted to hide were actually gifts that he had openly disclosed to the state.

In opening statements at the trial, Dimora's lawyers told the jury they would eventually see the forms, but Lioi later ruled they were hearsay and inadmissible evidence.

All three of the judges on the Appeals Court panel concurred that Lioi was wrong to bar admission of the forms. But in a 2-to-1 decision, the panel majority characterized Lioi's decision as "harmless error" that "more probably than not" would not have changed the verdicts had the forms been presented at the trial.

Grostic challenged that decision in his appeal to the Supreme Court, calling the state forms the key to Dimora's defense, and arguing that the decision to block them from the trial was not harmless but was serious error, and potentially could have changed the verdicts had they been allowed.

Other appeals courts across the country have diverged sharply on their interpretation and application of the harmless error standards, Grostic wrote in his motion. He is hoping the Supreme Court agrees to hear the Dimora case and resolve the debate by setting one legal standard for harmless error.

A spokesman for the U.S. Attorney's Office declined to comment on Dimora's request to the Supreme Court.

After the Appeals Court ruling April 30, the prosecutors said the decision confirmed that Dimora received a fair trial, and "the jury's verdict was supported by overwhelming evidence of (his) greed and corruption."