When corrupt public officials go to prison, how much of their sentence do they serve?

On Thursday, New York City Councilman Ruben Wills is scheduled to be sentenced to up to seven years in prison for stealing some $30,000 in public campaign funds and state grants.

His sentencing comes after John Sampson, the former leader of the state Senate Democratic conference, was sent to prison for for five years earlier this year. That’s the same length of time that Dean Skelos, the former Republican state Senate majority leader, is set to serve behind bars for his crimes, pending an appeal.

But if recent history is any indication, all three ex-lawmakers will get out of prison early.

“As you can imagine, the sorts of people who are convicted of these kinds of offenses will get their good time behavior – they’re unlikely to get into fights and to other things inside that will result in them not getting that time,” Jennifer Rodgers, executive director for Columbia Law School’s Center for the Advancement of Public Integrity, told City & State last year. “There are extraordinary situations where someone will seek a pardon or a medical allowance to get out early if they’re dying or something.”

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The punishments can only be reduced so much. That’s because a 1984 U.S. law requires that, which a few exceptions, anyone convicted on federal charges must serve up to 85 percent of their sentence before they are eligible for supervised release for good behavior. The 1984 Sentencing Reform Act also eliminated parole for defendants convicted of crimes.

The 85 percent threshold applies to the vast majority of offenders sent to federal prison. In 2012, the nearly 62,000 inmates released from federal prison had served an average of 88 percent of their sentences, according to the Bureau of Justice Statistics.

A number of convicted lawmakers have earned an early release in New York, including three disgraced former state senators: Shirley Huntley, whose sentence of a year and a day was reduced to 10 months; Efrain González Jr., who served just under six years of his seven-year sentence; and Vincent Leibell, who was sentenced to 21 months but got out after 17 months.

Sampson and Skelos would qualify for early release after 4 ¼ years. Other former lawmakers, like ex-Sens. Carl Kruger and Malcolm Smith and former Assemblyman William Boyland, could also benefit from early release.

But unlike those politicians who were convicted in federal court, Wills was prosecuted by state Attorney General Eric Schneiderman. Another high-profile figure prosecuted at the state level is William Rapfogel, the former CEO of the the nonprofit Metropolitan New York Council on Jewish Poverty, who was sentenced to between 3.5 years and 10 years in prison. After just 14 months he was transferred to a minimum-security prison where he was allowed to leave during the day to go to work, and he was freed in May after serving less than three years because he had served five sixths of his minimum sentence and qualified for merit release.

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For politicians convicted of federal corruption charges, it used to be easier to get out even faster. Former Bronx Democratic Chairman Stanley Friedman, who was sentenced to 12 years in federal prison as a series of scandals struck the Koch administration in the 1980s, was released after only four years. Another Koch associate, the former Bronx Rep. Mario Biaggi, was given a punishment of eight years in prison, with a minimum of 32 months. He ended up serving just 26 months, although the reason for his early release was a serious illness. (That ruling came into question when he ran for office the year after his release.)

Federal prisoners can still seek clemency or a pardon for a terminal illness. Former state Senate Deputy Leader Tom Libous was convicted of federal charges in July 2015, but due to his terminal case of cancer, he was sentenced to only six months of home confinement. Hedied last year, and his sentence was vacated.

But Kevin McCarthy, a professor at John Jay College of Criminal Justice and a former federal prosecutor, told City & State last year that federal prisoners being released due to a terminal illness is “very rare.”

Indeed, former Assemblyman Anthony Seminerio was sentenced to six years in prison following a bribery conviction and died in 2011 before serving even one full year.

“They do provide medical services in the federal system, especially there are number of facilities that focus on medical care,” McCarthy said. “But I think after serving a period of time, if this person is truly terminal, there can be a hardship release, but those are rare and generally most people with terminal illnesses actually die in prison.”

NYPIRG Executive Director Blair Horner said that for many disgraced officials, the damage has already been done by the time they are sent to prison.

“I don’t know how much the public is going to pay attention to how much time they actually serve in the pokey,” he said. “I mean, people don’t remember how many of the months Alan Hevesi was supposed to be in prison versus what he actually served. He was just like a ghost – just a political ghost.”

Hevesi, a former state comptroller, was sentenced in April 2011 to one to four years in a state prison for corruption. He was released and granted parole in November 2012.

“If the verdicts come down and they get multiple years in prison and huge financial penalties, that’s a big price to pay. Whether or not they end up getting out after 80 percent of their time because of good behavior, I don’t think it’s going to make that big of a difference,” Horner said. “They’ve been toppled from the heights of political power, they’ve been financially bankrupt and they’re facing time in the slammer – that’s brutal and they’re not young guys, so they’re going to be spending their golden years in orange jumpsuits.”

With reporting by Ashley Hupfl.