A judge has called former US House Speaker Dennis Hastert a "serial child molester" and sentenced him to 15 months in prison in a hush money case tied to decades-old abuse.
Hastert, who pleaded guilty last year to violating banking law, becomes one of the highest-ranking politicians in US history to go to prison.
The 74-year-old admitted in court for the first time on Wednesday that he "mistreated" former student-athletes when he was a high school teacher and coach from 1965 to 1981.
Hastert (top right) with Stephen Reinboldt (bottom right)
"The thing I want to do today is say I'm sorry to those I hurt and misled," Hastert said.
"First I want to apologise to the boys I mistreated when I was a coach. What I did was wrong and I regret it."
Before handing down the sentence, Judge Thomas Durkin said: "Some conduct is unforgivable no matter how old it is."
Hastert was once second in line to the US presidency
In addition to his prison term, Hastert was ordered to undergo sex offender treatment and pay $250,000 to a crime victims' fund.
Earlier, a man who accused Hastert of molesting him decades ago testified that he "felt intense pain, shame and guilt".
Scott Cross, now 53, fought back tears as he described being sexually abused while a member of Hastert's wrestling team.
"As a 17-year-old boy, I was devastated. I tried to figure out why Coach Hastert had singled me out," he told the court.
When it was his turn to speak, Hastert said he did not remember the victim specifically, but admitted that he abused others.
Hastert pleaded guilty last year to violating banking laws when he agreed to pay $3.5m (£2.4m) to someone to keep quiet about "prior misconduct".
The charges lifted a veil of secrecy from allegations that he had molested students, and sent shock waves through Washington, where he was second in line to the US presidency as House Speaker from 1999 to 2007.
It was alleged in court documents that Hastert sexually abused at least four students, ranging in age from 14 to 17.
Mr Cross, who until Wednesday had been identified as individual D in court papers, said he finally revealed the abuse to his wife and parents last year after Hastert's arrest.
"Staying silent for years was worse," he said. "It is important to tell the truth. ... I could no longer remain silent."
The sister of another alleged victim told the court that Hastert abused her brother throughout his years at Yorkville High School.
Jolene Burdge said her brother, Stephen Reinboldt, who died of AIDS in 1995, felt "betrayed, ashamed and embarrassed".
She urged Hastert to not be a "coward" and to "tell the truth"