As he vowed to do, Ray Nagin has formally appealed his conviction on corruption charges to the U.S. 5th Circuit Court of Appeals.

Whether the federal government counters with an appeal of the lenient 10-year sentence a federal judge handed the former mayor last week remains to be seen.

In a one-paragraph court filing Tuesday, Nagin said he would challenge the district court’s “verdict, sentencing, fine, assessment and forfeiture,” among other issues.

Last week, U.S. District Judge Ginger Berrigan sentenced Nagin to a decade behind bars after a jury convicted him in February on 20 of 21 counts.

Neither Nagin’s attorney, Robert Jenkins, nor officials with U.S. Attorney Kenneth Polite Jr.’s office responded Tuesday to calls seeking comment.

Nagin’s filing sets the stage for a last-ditch bid to avoid a Sept. 8 date to begin serving his sentence while also starting to pay $500 a month in restitution. Berrigan last week ordered the two-term former mayor to pay another $84,264, on top of the $501,000 he owes the federal government for “ill-gotten gains” from a series of bribery schemes for which he was convicted.

Veteran defense attorney Pat Fanning said Nagin appears to hold little traction for a strong appeal.

“Whatever his best shot is, that’s a little like being the tallest midget in the circus,” Fanning said. “I’m thinking he doesn’t have a great shot.”

Still, Fanning said, Nagin can appeal based on a so-far rejected argument of prosecutorial misconduct built on the now-infamous online rantings of former federal prosecutor Sal Perricone, who leveled some harsh invective at the former mayor. Federal prosecutors have successfully rebuffed those arguments to date, saying Perricone never played a significant role in Nagin’s case.

Jenkins also could try arguing racial bias in the selection of the jury that convicted Nagin. It’s a common legal argument in such appeals, and one that may have been raised amid disagreements aired privately with Berrigan during jury selection, Fanning said.

Among the 12 jurors and four alternates ultimately selected for the February trial, 13 were white, one black and two Asian. Nagin is African-American.

Fanning said it’s doubtful that Nagin could win on a claim of “ineffective assistance of counsel,” despite criticism by some legal observers of Jenkins’ defense of the former mayor.

“There’s a different standard when you choose your own counsel” than when a defendant is assigned a public defender, Fanning said. Besides, he said, “I don’t think anybody is going to think Robert Jenkins did a crappy job when the case ends up with a defendant getting one third less (time) than any of the guidelines.”

Berrigan’s 10-year prison sentence for Nagin fell well below the 15- to 20-year term called for in federal sentencing guidelines. The judge justified her leniency in part by citing the 58-year-old mayor’s age and the remote possibility that he will ever be able to violate the public trust again. She also noted that Nagin’s “reputation and credibility have been almost irreparably harmed” and said she doesn’t believe his crimes were completely motivated by selfishness.

Whether Polite’s office, in conjunction with the U.S. solicitor general, decides to appeal Berrigan’s sentence may prove to be Polite’s biggest decision since taking over the office last year, in the wake of longtime U.S. Attorney Jim Letten’s resignation in late 2012 as the blogging scandal engulfed the office.

Follow John Simerman on Twitter, @johnsimerman.