In 2006, Cyntoia Brown was convicted of murdering a man who hired her for sex and sentenced to life in prison. She was sixteen years old. Brown testified that she killed the man in self defense, that she was forced into prostitution by an abusive boyfriend after escaping an abusive home. None of that mattered in the Tennessee court where she was tried as an adult.

Brown is far from alone. She is one of about 10,000 Americans serving life sentences for offenses committed as a child, meaning under the age of eighteen. Of them, approximately 2,500 are serving an even more dire sentence—life without the possibility of parole (LWOP). The United States is the only country in the world that sentences people to die in prison for offenses committed as children.

The U.S. has been grappling with how to address crimes committed by children for centuries. As early as 1899, U.S. jurisdictions began creating the world’s first juvenile courts, which held children less culpable for their crimes, diverting many away from adult prisons. Within decades, however, these courts found themselves under attack by prosecutors and others who feared they were too lenient on dangerous underage murderers. During the 1980s and 90s, the power of juvenile court judges was greatly reduced, with a corresponding increase in power for prosecutors and criminal trial courts, allowing thousands of teenagers like Cyntoia Brown to receive life sentences.

Since 2005, several key Supreme Court decisions and individual state laws have sought to protect children from the most extreme sentences, but even these reforms have faced significant resistance from prosecutors and lawmakers.

* * *

“The past decade marks a revolution in the attitude of the state toward its offending children,” proclaimed a 1909 Harvard Law Review article by Julian W. Mack. Until then, Mack wrote, “our common criminal law did not differentiate between the adult and the minor who had reached the age of criminal responsibility,” leaving child offenders “huddled together” with adults in jails and workhouses. Before the juvenile justice “revolution” he described, the age of criminal responsibility in U.S. states ranged from 7 to 12.

This harshness toward children derived from traditional English common law, which convicted and punished 7- to 14-year-old children as long as they appeared to understand the difference between right and wrong. There are records of children as young as 10 put to death in eighteenth century England.

In the second half of the nineteenth century, U.S. reformers pushed for the creation of juvenile court systems that would seek to rehabilitate—not just punish—child offenders. As the legal scholars David S. Tanenhaus and Steven A. Drizin outline in a 2002 paper in the Journal of Criminal Law and Criminology, the first juvenile court opened in 1899 in Cook County, IL (home of Chicago), thanks to reformers Lucy Flower and Julia Lathrop. By 1909, more than 30 American jurisdictions adopted similar legislation, as did Great Britain, Ireland, Canada, and Australia.

Writing in 1909, Mack captured the prevailing view toward reform over punishment: “the child who has begun to go wrong, who is incorrigible, who has broken a law or an ordinance, is to be taken in hand by the state, not as an enemy but as a protector, as the ultimate guardian.” Ideally, he wrote, convicted children should be placed on probation, assigned a guardian, and allowed to remain in their own homes and communities. In cases where removal from the home was deemed necessary, the Supreme Court of Illinois ordered that “a real school, not a prison in disguise, must be provided.”

“What they need, more than anything else, is kindly assistance,” wrote Mack. “The aim of the court in appointing a probation officer for the child, is to have the child and the parents feel, not so much the power, as the friendly interest of the state.” He quoted a Supreme Court of Utah decision, which declared that a juvenile judge must be “a man of broad mind, of almost infinite patience, and one who is the possessor of great faith in humanity.”

As the movement toward mercy and reduced culpability for children swept the nation, in 1920 criminal law journal article, Arthur Towne, the superintendent of the Brooklyn Society for the Prevention of Cruelty to Children, considered whether New York State should follow other states in increasing its age of criminal responsibility from 16 to 18, asking:

Does he go to bed the night before his sixteenth birthday, a tender boy in need of the state’s solicitude, and awaken the next morning a bearded man, full-fledged in experience and self-control, and in ability to fulfill his obligations as a citizen? Upon donning his long trousers does he forthwith become a man; or in spite of his somewhat lengthened years and clothes, may he still be in his short “pants” mentally and morally?

Writing in 1920, Towne said adolescence continues through age 25, and that treating 14- or 16-year olds as functioning adults “simply flies in the face of present-day psychology and the hard facts.”

***

Despite Towne’s advocacy, New York State did not stop automatically charging 16- and 17-year-olds as adults until April 2017. Juvenile courts faced decades of backlash, as prosecutors argued for discretion over whether individual cases should be heard in juvenile or criminal court. In a series of decisions, the Illinois Supreme Court stripped power from the juvenile courts, granting the state’s attorney the authority to decide in which court a child would be tried.

Beginning in the 1930s, prosecutors pushed for more power, claiming that the nation faced a dangerous new class of child murderers. In 1935, the Chief Justice of the Illinois Supreme Court declared that juvenile courts were intended for “bad boys and girls who have committed no serious crime,” but were being used to protect “highly dangerous gunmen and thieves, or even murderers.” But even as juvenile courts were being undermined, they were simultaneously legitimized. In the 1960s, U.S. Supreme Court decisions guaranteed due process protections in juvenile court, including the right to counsel.

In 1978, the “automatic transfer law” was born. A 15-year-old New Yorker named Willie Bosket was convicted of killing two men on the subway. He was tried in juvenile court and received the maximum juvenile sentence of five years. Two days later, New York Governor Hugh Carey (in the middle of a tight re-election battle) called a special session of the legislature to produce the Juvenile Offender Act. This “automatic transfer law” required children as young as 13 to be tried as adults for murder.

Attacks on the power of the juvenile court intensified in the 1980s and 90s. “These cries grew to a fever pitch with the birth of the ‘superpredator’ myth in late 1995,” wrote Tanenhaus and Drizin. Academics, prosecutors, and lawmakers criticized juvenile courts, using “the sound bite ‘adult time for adult crime’ as their mantra.”

Between 1990 and 1996, forty states passed laws making it easier for juveniles to be prosecuted as adults, often by transferring power from juvenile judges to prosecutors. Other new laws prevented the sealing of juvenile records, set mandatory minimum sentences, or removed phrases like “rehabilitation” and “the best interests of the child” from statutes, replacing them with “punishment” and “the protection of the public.”

The new laws kept coming, with 43 states passing similar changes between 1996 and 1999. A 1999 report found that when juveniles were transferred to adult court and convicted of murder, they received, on average, longer sentences than adults convicted of the same crime. In 1998, close to 200,000 kids were tried as adults and 18,000 were housed in adult prisons.

“Teenagers account for the largest portion of all violent crime in America,” declared then-Florida representative Bill McCollum in 1996. “They’re the most violent criminals on the face of the earth.” He was arguing in support of an ultimately failed federal bill that would have required some 13-year-olds to be tried as adults.

As children were increasingly tried as adults, racial minorities suffered the most. In 1997, white children made up 57 percent of juvenile cases involving offenses against others, but just 45 percent of the cases transferred to adult court. And while white youth constituted 59 percent of juvenile drug cases, they made up just 35 percent of the cases transferred to adult court.

Clinging to the “superpredator” myth, prosecutors parroted colorful claims about the nineteenth century mischief-makers that juvenile courts had been created for. According to various District Attorney’s offices, the courts were created “when kids were throwing spitballs,” “when kids were knocking over outhouses,” and “at a time of more ‘Leave it to Beaver’ type crimes.”

***

While attorneys and politicians panicked about the rise of the “superpredator,” juvenile crime actually declined between 1994 and 2000. A 2001 U.S. Surgeon General’s report found that “there is not evidence that the young people involved in violence during the peak years of the early 1990s were more frequent or more vicious offenders than youth in earlier years.”

As it turns out, there have always been murders by children. Using the Chicago Homicide Database, Tanenhaus and Drizin located the cases of 24 children tried for homicide by juvenile courts in the early 1900s. They wrote that these cases “reveal that the juvenile court was created at a time when kids were not only throwing spitballs and knocking over outhouses, but they were also killing people.” These cases show how children were protected from the adult criminal system, thanks to multiple checks on the power of prosecutors.

In one 1910 case, a 12- or 14-year-old girl (accounts differ) was accused of beating an 8-year-old girl to death with a baseball. A “coroner’s jury” was summoned: a group of citizens convened to determine cause of death. “Owing to the extreme youth of the accused,” declared the coroner’s jury, “the Jury recommend that she be permitted to remain in the custody of her parents for the present until the case is taken up by the Juvenile Court.” The authors note that coroner’s juries were rife with corruption and graft. Yet in this case and others, they did serve as a check on prosecutors, helping keep children out of adult court.

In a 1908 case, twin 13-year-old boys were tried for stabbing a schoolmate to death with a letter opener. Although the coroner’s jury recommended the boys go before an adult court, they were protected by other checks on the system: The grand jury ruled there was insufficient evidence to prosecute one twin, and the state officially declined to prosecute the other.

In a third case, in 1926, four 15- and 16-year-old boys were arrested in a shooting death. They took various paths through the court system, with some starting in the adult criminal system and some in the juvenile—yet ultimately, none were prosecuted as adults.

The 24 cases studied by Tanenhaus and Drizin are a small sample, but demonstrate that murders by children were far from new in the 1980s and 90s. What was new was the state’s harsh punishments.

* * *

In the 2000s, criminal justice reform gained traction. According to the ACLU, “after decades of punitive ‘tough-on-crime’ responses to youth crime and misbehavior, there has been a perceptible shift in recent years surrounding juvenile justice issues in the United States. Policymakers are slowly returning to the first principles of juvenile justice by recognizing that young people are still developing and should be given opportunities for treatment, rehabilitation, and positive reinforcement.”

An early turning point came in 2005, when the U.S. Supreme Court determined that death sentences for children violate the 8th amendment’s prohibition on cruel and unusual punishment in Roper v. Simmons. Over the next 10 years, the Court expanded on Roper, chipping away at the sentences that children may receive. First, in 2010, Graham v. Florida made it unconstitutional to sentence a child to LWOP for any crime other than murder. Two years later, Miller v. Alabama made it illegal for states to impose mandatory sentences of LWOP for juveniles (judges may still use their discretion to give the sentence in rare cases of “irreparable corruption,” but the sentence cannot be mandated).

The Supreme Court based these decisions on fundamental scientific differences between adult and child brains. The Court’s Miller decision quoted a brief from the American Psychological Association: “It is increasingly clear that adolescent brains are not yet fully mature in regions and systems related to higher-order executive functions such as impulse control, planning ahead, and risk avoidance.”

In yet another groundbreaking case, the Supreme Court made the Miller decision retroactive in 2016’s Montgomery v. Louisiana. As a result, the roughly 2,500 people serving LWOP for crimes they committed as children are eligible for resentencing hearings.

Montgomery does not reduce anyone’s sentence automatically. Each county is responsible for its own resentencing, and District Attorneys around the U.S. have interpreted the Supreme Court’s order differently. In Philadelphia County, which previously held the record for the most people serving juvenile LWOP, resentencing hearings are moving relatively quickly. At least seventy people have already been resentenced, paroled, and released. In Michigan, meanwhile, county prosecutors have announced their intentions to re-seek LWOP in 247 out of 363 juvenile cases, essentially claiming that 68 percent of kids sentenced to life without parole fit the “rare” label of “irreparable corruption.” And in Louisiana, 71-year-old Henry Montgomery, the man for whom the case was named, remains incarcerated after getting a new sentence of life with the possibility of parole.

Miller and Montgomery do nothing for children serving other extreme sentences. Cyntoia Brown, who is unaffected by Montgomery because she is serving a regular life sentence, recently applied for clemency to Tennessee Governor Bill Haslam. She could become immediately parole-eligible if the governor commutes her sentence to time served. Without clemency, Brown will have her first shot at parole in 2055, when she will be 67 years old.