This story was co-published with Buzzfeed

After a three-year legal battle, Iowa's highest court has thrown out the sentence of Nick Rhoades, who was sentenced to 25 years in prison and lifetime sex offender registration for criminal transmission of HIV.

Rhoades, whose case was central to a ProPublica investigation published last year, pleaded guilty to the charge in 2009 after failing to inform a one-time sexual partner that he was HIV-positive.

The investigation, co-published with BuzzFeed, found 541 cases across 19 states in which defendants were convicted or pleaded guilty to similar crimes. Some incurred harsh penalties even though they had not infected anyone or had used protective measures, such as wearing condoms or taking antiviral drugs that reduced the risk of transmitting HIV.

In a 6-1 ruling issued last week, Iowa's Supreme Court set aside Rhoades' sentence, saying his trial lawyer provided ineffective counsel when he allowed Rhoades to plead guilty to a charge for which there was no factual basis.

Specifically, the court said, prosecutors had not established whether Rhoades exposed his partner, Adam Plendl, to his bodily fluids; whether such exposure was intentional; and whether such exposure was likely to "result in the transmission of HIV."

The third point has been at the center of debate over laws such as Iowa's, many of which were enacted before the advent of modern HIV drugs. Critics, including Lambda Legal, the gay rights group that argued Rhoades' case, claim these laws unfairly target people with HIV and have not kept pace with medical knowledge about transmission, treatment and prevention.

The Iowa decision appeared to embrace this argument. When Rhoades pleaded guilty, the court said, it was still unsettled "whether it was medically true a person with a nondetectable viral load could transmit HIV through contact with the person's blood, semen or vaginal fluid or whether transmission was merely theoretical," the court said.

But citing "great strides in the treatment and the prevention of the spread of HIV," the justices said sexual contact alone is no longer enough to establish whether a person can transmit HIV.

"We would not want to deprive a person of his or her liberty on the basis the defendant's actions caused something that can only theoretically occur," the court said.

In an email following the decision, Rhoades, now 39, lauded the ruling, calling it "a victory for EVERYONE living with HIV."

"I truly hope our luck continues and the wind has changed direction," he said.

Scott Schoettes, one of Rhoades' lawyers and Lambda Legal's HIV project director, said the court's ruling could transform the way other states interpret and apply their own HIV laws. Currently, at least 35 states have laws that specifically criminalize exposing another person to HIV. In 29 states, it is a felony.

"Many states hinge criminal liability for exposure to HIV on whether the virus 'could' be transmitted by a particular activity—and this has been interpreted by most (maybe all) U.S. courts to mean that there is any possibility of transmission," Schoettes wrote in an email to ProPublica. But the Iowa decision, he said, "established that a mere theoretical possibility is not enough and that the potential harm must be 'reasonably possible' before criminal sanctions should attach."

Schoettes said Lambda plans to use the Iowa ruling to press similar arguments in other jurisdictions.

From a practical perspective, the court's decision will change little for Rhoades.

After spending several months in state prison in 2009, a lower court commuted his sentence from 25 years in prison to five years of supervised probation, a term that would end in September.

The decision also came two weeks after Iowa Governor Terry Branstad signed a bill revising the state's HIV transmission law and installing a tiered sentencing structure that considers whether offenders intended to expose their partners to the virus and whether HIV transmission actually occurred.

The new law eliminates the sex offender registration requirement for offenders and includes a retroactive provision to remove anyone convicted under the old statute—such as Rhoades—from the state's registry.

The bill drew support from local HIV activists and the Iowa Department of Public Health, but was opposed by some advocates nationally because it creates new felony offenses for intentionally exposing people to other diseases.

"In this case, an improvement for people living with HIV in Iowa represents a substantial worsening of the treatment of meningococcal disease, hepatitis, and tuberculosis," said the Center for HIV Law and Policy in a statement, which authored a friend-of-the-court brief in the Rhoades case.

Lambda's Schoettes praised some aspects of the new law, but criticized provisions providing "safe harbor" to people with HIV only if they wear condoms, even when they are undergoing treatment.

"If they tried to pass a law that required HIV-negative people to wear condoms while having sex, people would—legitimately—rise up in protest at this egregious violation of their civil liberties," Schoettes said.

With the passage of the new measure, Iowa became the first state to radically overhaul its HIV law. Illinois passed a bill amending its law in 2012 and legislators in Washington have introduced bills seeking to update its HIV exposure statute. Since ProPublica's story was published in December, federal lawmakers have also introduced legislation that would incentivize states to reexamine their HIV laws, and the U.S. Department of Justice and Center for Disease Control and Prevention published a joint review of state laws in the Journal of AIDS and Behavior.

Rhoades' case will now be remanded to the Black Hawk County trial court and prosecutors will need to decide whether to take the case to trial, negotiate a new plea deal, or withdraw the charge.

"We will review the investigation and the court decision and make that determination with the victim and our Attorney General's office," said Black Hawk County Attorney Tom Ferguson in an email Friday, adding that his office was still "reviewing and digesting" the court's ruling.

Plendl, the man Rhoades had sex with, did not respond to ProPublica's requests for comment. It is unclear whether Plendl—who, at Rhoades' sentencing hearing in 2009, asked the court to impose the maximum, 25-year sentence—would still cooperate with prosecutors today. He no longer lives in Iowa and, in an interview last year, said he now believes HIV exposure laws "need to be revisited."