NASHVILLE (AP) — A federal appeals panel is keeping a 21-month prison sentence in place for a former Tennessee state senator who tried to withdraw his guilty plea on campaign finance law violations.

The ruling Monday in the 6th U.S. Circuit Court of Appeals focuses on the August 2023 sentencing of former Sen. Brian Kelsey. The Republican had pleaded guilty to charges related to his attempts to funnel campaign money from his state legislative seat toward his failed 2016 congressional bid. His attorneys have argued that federal prosecutors violated Kelsey's plea agreement when they said a harsher sentence could be applied after he attempted to withdraw his guilty plea in March 2023.

Kelsey has remained out of prison during his 6th Circuit appeal under the lower court judge's order. A defense attorney for Kelsey, Alex Little, has told news outlets he plans to appeal the latest decision.

According to two of the three appellate judges, Kelsey's legal team failed to raise an objection about the alleged breach of his plea deal by federal prosecutors. The third judge said defense attorney raised the objection properly, but concluded that prosecutors did not breach the plea agreement.

In the opinion, Judge Karen Nelson Moore wrote that Kelsey still received a more favorable sentence than the guidelines for his offense spell out, with or without the sentencing enhancement that the judge applied for obstruction of justice.

"Notwithstanding the government's conduct, then, Kelsey received the key benefit of the plea agreement — a sentence not only within the range contemplated by the parties, but below it — so it is unclear how any breach prejudiced Kelsey," Moore wrote.

Prosecutors have contended that Kelsey broke his deal first when he tried to back out of his guilty plea and that a harsher sentencing would have been appropriate, but they ultimately chose not to seek the tougher sentence.

In a concurring opinion, Judge Raymond Kethledge wrote that prosecutors' comments on sentencing were an appropriate response to a question from the district judge, Waverly Crenshaw, and did not expressly request that the judge apply the sentencing enhancement.

In a statement, U.S. Attorney Henry Leventis said the 6th Circuit panel's ruling "should ensure that (Kelsey) will finally be held accountable for his actions."

In March 2023, Kelsey argued he should be allowed to go back on his November 2022 guilty plea because he entered it with an "unsure heart and a confused mind" due to events in his personal life; his father had terminal pancreatic cancer, then died that February, and he and his wife were caring for twin sons born the preceding September.

Crenshaw denied the change of plea in May 2023. He has expressed disbelief that Kelsey, a Georgetown University-educated attorney and prominent former state senator, didn't understand the gravity of his guilty plea.

Before that, Kelsey had pleaded not guilty, often saying he was being targeted by Democrats. But he changed his mind shortly after his co-defendant, Nashville social club owner Joshua Smith, pleaded guilty to one count under a deal that required him to "cooperate fully and truthfully" with federal authorities. Smith has been sentenced to five years of probation.

Kelsey, an attorney from Germantown, was first elected to the General Assembly in 2004 as a state representative. He was later elected to the state Senate in 2009. He didn't seek reelection in 2022.

Kelsey served as the chairman of the Senate Judiciary Committee, which oversees changes to civil and criminal laws, judicial proceedings and more.