A former US House speaker has been jailed for 15 months in a bribery case that centred on accusations that he sexually abused at least four students when he was a school wrestling coach.
Dennis Hastert must also undergo sex offender treatment, two years of supervised release after his time behind bars and pay a $250,000 fine to go to a crime victims fund.
He pleaded guilty last fall to violating banking law as he sought to pay someone referred to as Individual A $3.5m to keep sex abuse secret.
Before he sentenced Hastert, Judge Thomas M Durkin described the 74-year-old Illinois Republican as a "serial child molester", adding that "accusing Individual A of extorting you was unconscionable".
He was the nation's longest-serving GOP speaker and was second in the line of succession to the presidency.
Earlier in the hearing, a former athlete who said he was molested by Hastert decades ago told the courtroom that he was "devastated" by the abuse.
The man, now in his 50s, said Hastert abused him while they were alone in a locker room.
He struggled to hold back tears as he described the incident in detail. In the years since, he said, he sought professional help and had trouble sleeping. He said the memory still causes him pain.
He said he trusted and looked up to Hastert.
In his own statement, Hastert admitted that he "mistreated" some of his athletes and said he was "deeply ashamed".
"I am sorry to those I hurt and misled," he said. "What I did was wrong and I regret it."
When the judge asked whether he sexually abused one wrestler specifically, Hastert said yes.
Moments before the man took the stand, a woman who says her brother was sexually abused by Hastert told the courtroom that her sibling felt "betrayed, ashamed and embarrassed".
Jolene Burdge said Hastert abused her brother, Stephen Reinboldt, throughout his years at Yorkville High School, where Hastert was a history teacher and coach from 1965 to 1981.
Reinboldt died of Aids in 1995.
His sister turned toward Hastert and said: "Don't be a coward ... tell the truth."
She also said: "I hope I have been your worst nightmare."
Authorities said Hastert abused at least four students throughout his years at the school about 45 miles south west of Chicago.
The 74-year-old, who was pushed into the courthouse in Chicago in a wheelchair, agreed to a plea deal that suggested anything from probation to a maximum of six months behind bars.
But after prosecutors lifted a veil of secrecy from the case, the judge made comments suggesting he might impose a longer sentence, potentially putting Hastert behind bars for years, because of the abuse allegations.
Defense attorneys were seeking probation on the grounds that Hastert has already paid a high price in disgrace.
They also cited his health, saying a blood infection nearly killed him in November and that a stroke has limited his mobility.
The lead prosecutor said he wishes Hastert could have been charged with the abuse he was trying to cover up.
Assistant US attorney Steven Block called Hastert's conduct "horrendous". But because of the statute of limitations, he could only be charged with a financial crime related to the payments he was making to one of at least four victims of sexual abuse.
Block said the sentence should take into account that Hastert "continues to deny what should now be obvious to everyone," that the payments were to conceal sexual abuse.
Defence attorney Thomas Green said he "acknowledges and respects" the pain of the man who described being molested.
He urged the judge to take into consideration the "entire arc" of Hastert's life, asserting that he reshaped his life as a public servant during his political career.
"Decades of not just political achievement but acts of goodness and charity have been erased, a lot of it even physically as his name has been removed from public places and his portrait at the Capitol put into storage," Mr Green said.
Some letters of support were withdrawn because the writers did not want to be identified, Mr Green said, an example of Hastert's deepening isolation.