Kevin Ring, president of the prison-reform group Families Against Mandatory Minimums, knows the U.S. prison system intimately.
In the 1990s, Ring worked as a Republican Congressional staffer in both the House and Senate, helping push through a landmark 1994 crime law that established longer mandatory sentences -- including for criminals convicted of non-violent offenses.
Twenty years later, he began serving an 18-month sentence for public corruption and other crimes related to his later lobbying work.
Ring worked at the same firm as Jack Abramoff, the infamous lobbyist whose peddling of influence for cash was so egregious that Congress created a new ethics office in the wake of his scandal.
In 2008, Abramoff was convicted on corruption and tax-related charges and received a four-year sentence.
Ring was convicted in 2010, after an earlier mistrial. After a lengthy series of appeals he began serving his time in a minimum-security facility in 2014.
The turning point in his life, Ring says, "from being a tough-on-crime hill staffer to a defendant," was soon followed by one of the worst: Being forced to explain to two young daughters that he was going to prison.
"Locking someone up in a cage is the worst thing we can do to a person, apart from putting them to death," Ring told CNBC in a recent phone interview.
Ring, now 47, says he was fortunate that the judge on his case had the power to imprison him for far less time than prosecutors had asked for.
"The thing that saved me (from a lengthy sentence) is that the judge knew my background and had the discretion" to impose a lighter sentence.
Now he's working to reduce the prison sentences of other non-violent offenders.
Ring is one of a handful of former GOP political insiders turned federal prisoners now advocating for criminal justice reform. FAMM is funded in part by the Koch brothers, among the largest donors to conservative causes.
Two others are David Safavian and Pat Nolan, the deputy director and director of the Center for Criminal Justice Reform, which is a unit of the powerful conservative lobbying group, the American Conservative Union Foundation.
Safavian, also caught up in the Abramoff scandal, was convicted of obstruction of justice and making a false statement and served a year in federal prison a decade ago. Nolan, a former California state legislator who was GOP leader of the California Assembly in the mid-1980s, was caught up in an FBI sting operation known as Shrimpscam." He pleaded guilty to one count of racketeering and spent two years in jail.
Along with their conservative politics and first-hand experience with the prison system, the three men share another surprising thing in common: Their advocacy groups recently received funding from the Chan Zuckerberg Initiative, which has made criminal justice reform one of its priorities -- along with education, housing and science.
After a 2015 visit to San Quentin, the famous Bay Area prison near San Francisco, Facebook CEO Mark Zuckerberg said the U.S. "can't jail its way to a just society."
"We're building the wrong social network for those kids. Instead of showing them good role models, they're surrounded by people who are bad," he said.
"You don't want those kids to be affected that way. If you go to prison early in life, you'll be more likely to go later in life," said Zuckerberg, calling prison reform "one of the biggest things we're working on."
Thanks to support from both conservatives and progressives, 30 U.S. states have adopted some version of prison reform in the last 10 years. Ohio voters just passed a new amendment to the state constitution that expanded legal notification rights for crime victims.
Five of the states — including ones like Texas and Louisiana with tough-on-crime reputations — passed broad measures based on a concept called 'justice re-investment.'
That's the idea that America should build fewer prisons and reduce sentences, then use the cost savings for victim-compensation funds, anti-recidivism programs and hiring more police.
The GOP move toward prison reform — long a cause of the progressive left — began in Texas with Rick Perry, the former governor and 2016 Republican presidential candidate.
Faced with the cost of building several new prisons, Perry opted instead for a broad package of reforms. The result: the lowest crime rates in decades and more than $3 billion in savings.
"It's not just about reducing sentences," says David Safavian of the Center for Justice Reform. One key to lowering the prison population is to make sure released inmates have a "family support structure...and a meaningful job," he says. "If we check those two boxes, recidivism rates plummet," Safavian says.
According to a March 2016 report from the U.S. Sentencing Commission, more than half of federal prisoners released in 2005 were re-arrested for a new crime or for violating their supervision conditions by 2016.
These conservatives, along with left-leaning groups like JustLeadership USA, which is also funded by Chan Zuckerberg, have now taken their successful push for prison reform to Washington.
This year, several bipartisan bills targeting some type of criminal justice reform have been introduced in the Senate or House, one by Sen. Charles Grassley, the powerful head of the Senate Judiciary Committee.
One of the biggest potential obstacles, however, is Jeff Sessions, the Attorney General and former Senator and committee chair who in the past has blocked attempts to roll back mandatory minimums.
Late last month, though, Grassley said that Sessions, his former colleague, was willing to work with the Senate on sentencing reform.
Whether that will be enough to get it through the more-conservative House is unknown.
Using their lobbying skills, these groups are "educating" lawmakers on the benefits of not locking up non-violent offenders for lengthy sentences.
Safavian says the ACUF is also using Facebook to help connect prosecutors with other law enforcement officials for events that help build a consensus on prison reform.
"We're learning from them (CZI) how to impact the political process" using social media, he says.
If Facebook's targeting technology can do for criminal justice reform what it did for President Donald Trump's political career, FAMM's Kevin Ring may fulfill what he says is a personal and professional goal.
"I don't want to do this (work) forever," Ring says. "I want to put myself out of business."