Boston was the first American city to organize community-based patrols known as night watches. New York and Philadelphia followed suit in 1658 and 1700. Sometimes backed up by professional constables, a group of volunteers walked and rode horses around town, looked for suspicious or unfamiliar people, and warned citizens of danger.

Before the Revolution, there was no unified American justice system. Each colony had its own laws, codes, punishments, procedures, and court systems. The Founding Fathers used the drafting of the Constitution as an opportunity to provide uniform laws and rights.

Prior to the 18th century, virtually all criminal sentences involved either fines, execution, or gruesome tortures like flogging, branding, and cutting off noses and ears. Primitive jails were built, but only to hold suspects awaiting trial or sentence—incarceration was not a punishment in and of itself. As an increasingly sensitive public grew weary of gory corporal punishments and frequent executions, prison time began to emerge as an alternative approach.

The first slave patrols were organized in South Carolina in 1704 and became an integral part of antebellum Southern society. Organized groups patrolled forests and roads looking for runaways, illegal gatherings, and contraband—but their primary purpose was to instill terror and deter slave revolts. After the Civil War, police departments and sheriffs’ offices across the South were modeled on slave patrols, and their ranks were frequently populated with former slave patrollers.

The protections American citizens can expect in the criminal justice system were put into writing in 1791 with the adoption of the Bill of Rights. The first 10 amendments to the Constitution guarantee specific rights and freedoms for the individual and set the rules for due process in the application of the law. They also, however, leave a lot open to interpretation with strikingly subjective language, particularly the Eighth Amendment, which forbids the state from imposing "excessive bail," "excessive fines," and "cruel and unusual punishment."

In the 1820s, wardens at Auburn Prison in New York and Eastern State Penitentiary in Pennsylvania began experimenting with techniques to reform prisoners instead of merely punishing them. The experiments included complete silence and near-total isolation with no contact with the outside world and virtually no communication with guards or other inmates. The other two ingredients were hard work under the threat of corporal punishment and intense study of the Bible during long hours of silence and solitude.

In 1838, Boston created America’s first full-time professional police department. New York City, Chicago, New Orleans, Cincinnati, Philadelphia, and Baltimore soon followed, and by the 1880s, every major city had a municipal police force.

In 1857, the fledgling NYPD adopted a new technique that would change law enforcement forever. Police began photographing the city’s very worst known criminals and compiling their pictures in a special book to help victims identify potential suspects. The book was called the “Rogues’ Gallery.”

The 13th Amendment outlawed slavery “except as a punishment for crime whereof the party shall have been duly convicted.” It was a glaring loophole that directly tied a person’s most basic rights to their status in the criminal justice system. Through peonage, convict leasing, chain gangs, and prison plantations, Southern states would soon use the 13th Amendment to criminalize former enslaved people back into slavery.

After the Civil War, shell-shocked Southern whites introduced "Black Codes" to legally subjugate the millions of former slaves now roaming free, voting, going to school, and even running for office. The restrictive laws—applying only to African Americans—criminalized virtually every aspect of Black life and ensured that nearly every African American was in perpetual violation of the law. Any who were deemed troublesome, rebellious, dangerous, lazy, or even discourteous could be arrested for Black Code violations—most commonly vagrancy—and returned to slavery through the convict-leasing system.

From the Civil War through World War II, law enforcement in Southern states arrested and convicted tens of thousands of African Americans who had committed no real crime and leased them to farming and industrial operations as slave labor. Virtually any Black person who wasn’t working for a white man could be charged with vagrancy, convicted in corrupt local courts, levied unpayable fines, and then forced to perform hard labor until the fine was paid off by the companies that leased them—or they died. They toiled in terrible conditions in mines and on farms, and since they came cheap and were easy to replace, their lives and bodies were much less valuable than even those of their enslaved ancestors.

After the Civil War, a new breed of cops and criminals became legends in rugged and violent outpost towns that sprung up around railroad stops in the American West. Famed outlaws like Billy the Kid, Butch Cassidy, and Jesse James tried to stay a step ahead of iconic lawmen like Wyatt Earp and Seth Bullock in towns like Tombstone, Arizona, Deadwood, North Dakota, and Abilene, Texas.

Few symbols are more synonymous with the Wild West than the ‘Wanted’ posters that law enforcement used to seek the public’s help in catching criminals. Allan Pinkerton, founder of the famed Pinkerton Detective Agency, used such a poster for the first time in a kidnapping case in 1874. They would spring up all over the country, often advertising monetary bounties and—for the very worst outlaws—the qualifying statement of “dead or alive.”

In the 1880s, famous and controversial NYPD Chief Detective Thomas F. Byrnes expanded the Rogues’ Gallery concept as part of his pioneering innovations in police work. Instead of just photographing the very worst known criminals, he ordered his officers to take front and side-profile pictures of everyone they arrested. It was the first use of universal booking photos, which would make up the first law enforcement database.

On Aug. 6, 1890, a convict named William Kemmler was executed in New York in the world's first use of the electric chair. Although the terrifying new device looked like something out of the Inquisition, its proponents promised it would be a quick, painless, and humane alternative to old-world executions. It was not, and Kemmler writhed in agony for several minutes as his body burned from the inside out as horrified spectators watched.

Once the public learned of the brutal violence and rampant corruption that defined the convict-leasing system, Southern governments were pressured to regain control of the convicts they had been renting out. They achieved this by organizing them into chain gangs of slave laborers who did the backbreaking work of improving the South’s dilapidated infrastructure. Vagrancy and other Black Code violations kept the chain gangs full, and conditions were often as terrible as they were in the convict-leasing system.

At the turn of the 20th century, prison farms like the infamous Parchman Penitentiary in Mississippi began springing up across the South as an alternative to convict leasing and chain gangs. Malnourished, exhausted, and terrified convicts picked cotton and plowed fields under the threat of the whip, often on the exact same plantations where their ancestors toiled as enslaved people—and the conditions weren’t much different. To save money on guards, wardens bribed the most violent and feared prisoners, or “trustees,” to control inmates, many of whom died from heat exhaustion, disease, malnutrition, gunshots, beatings, medical neglect, and shackle poisoning.

In 1910, a Chicago man named Thomas Jennings was convicted of murdering a man in his home. Fingerprints Jennings left behind on a freshly painted railing were used to help convict him at trial. It is the first known conviction based on fingerprint evidence in the American justice system.

In 1920, the 18th Amendment banned the production, sale, importation, and consumption of alcohol in the United States. Much like the war on drugs that would follow, Prohibition gave rise to a far deadlier and more organized breed of criminals and put law enforcement on steroids. Consumption never waned, and when Prohibition was repealed 13 years later, alcoholism was still there.

Al Capone was the most famous gangster of the Prohibition era, but he was hardly the only one. The cartel kingpins of their time, gangsters like Capone accumulated enormous wealth and power through the illegal alcohol trade. They enforced their will and defended their turf with a level of violence that would have been excessive even by the standards of the Wild West outlaws who came before.

The FBI was formed in 1908 to unify law enforcement at the federal level in what had become a sprawling, continental country. The agency came into its own in 1924 when J. Edgar Hoover was appointed as its head. He would reign—arguably as the most powerful man in America—for nearly a half-century until 1972 and go down as the most controversial and effective lawman in history.

During the Depression, a brazen and deadly new brand of criminals emerged, one very different from organized crime syndicates like those headed by Al Capone. Freelance gangsters like Bonnie and Clyde, John Dillinger, “Machine Gun” Kelly, and “Baby Face” Nelson went on cross-country crime sprees, robbing banks, taking hostages, and killing police and civilians alike. Using Thompson submachine guns, Browning Automatic Rifles, bulletproof vests, and fast, powerful, V-8 cars, they surprised and overwhelmed local law enforcement everywhere before zooming off to the next jurisdiction.

Every cop show on television traces its roots to “Dragnet,” which began as a radio program in the 1940s before moving to television in 1951. It spawned the police procedural genre, one of the most successful and enduring in television history. The courteous, level-headed, and diligent Joe Friday’s pursuit of “just the facts” also provided excellent PR for the Los Angeles Police Department and law enforcement in general.

1960 signaled the start of an unprecedented increase in crime that would continue for decades before peaking in the 1990s. The rise of drugs, crime, gangs, and violence terrified the nation and resulted in harsh policies that would militarize law enforcement and fill America’s prisons. Between 1960-1970, crime rates soared by 126% before rising by another 64% between 1970-1980.

In March 1965, President Lyndon Johnson declared a "war on crime" and presented Congress with legislation that would forever change the nature of the American justice system. The Law Enforcement Assistance Act established a federal role in local law enforcement, including police, prisons, and the courts. Among other things, it created a channel that continues to transfer military weapons and equipment from the defense sector to local law enforcement to this day.

Everyone who has ever seen “Law and Order” knows that cops have to read suspects their Miranda rights at the time of their arrests. In 1966, the Supreme Court threw out the rape and kidnapping convictions of a man named Ernesto Miranda. The police violated Miranda’s rights, the Court concluded, by interrogating him until he confessed without informing him of his rights to remain silent and to have an attorney present during questioning.

In 1970, the federal Racketeering Influenced and Corrupt Organizations (RICO) statute gave law enforcement a powerful new weapon in fighting organized crime. It was always hard to lock up crime bosses who rarely did any dirt themselves, but RICO allowed law enforcement to charge people just for being part of an ongoing criminal enterprise. It gained fame when then-U.S. Attorney Rudy Giuliani used it to convict John Gotti, the last true don of the New York City mafia, in 1992.

In 1971, Mississippi’s infamous Parchman Farm Penitentiary was the last remnant of old-world slavery in the United States. Underfed, tormented, mostly Black prisoners toiled for 15-hour days under the threat of the lash and violent “trustee” inmates who had total power over their lives and bodies. Finally, that year a court ruled that Parchman’s system of penal slavery and the tortures used to maintain it were cruel and unusual punishment—even if they didn’t violate the 13th Amendment.

In June 1971, President Richard Nixon declared a “war on drugs” and referred to drug use as “public enemy number one.” In the ensuing half-century, the unwinnable war has cost $1 trillion, filled America’s prisons, dispensed harsh sentences for non-violent drug-related offenses, and given rise to cartels in Latin America that put Al Capone’s crime syndicate to shame.

The last flogging sentence ever handed down by a court in the United States was carried out in Delaware's New Castle County Workhouse on June 16, 1952. Like countless others before him all over the country, the prisoner was tied to a wooden post and whipped by a prison warden with 20 heavy lashes on his bare back. In 1972, Delaware became the last state in the U.S. to outlaw the once-familiar whipping post.

The 1960s-1980s saw a disturbing increase in cases that involved two or more victims killed by the same person in separate incidents that followed a pattern. Serial killers captured the public’s imagination and gave rise to a new kind of police work that involved psychology and science as much as stakeouts and handcuffs. In 1972, the FBI launched its Behavioral Science Unit to profile, track, identify, and arrest serial killers.

In 1972, the Supreme Court ruled in Furman v. Georgia that the death penalty constituted cruel and unusual punishment. It was a complicated and narrow ruling, however, and applied only to a few specific cases. Although it temporarily voided 40 death penalty statutes, it was not a precedent-setting ruling and would soon be overturned.

The Supreme Court reinstated the death penalty with Gregg v. Georgia in 1976, just four years after it ordered a moratorium. The following year, convicted murderer Gary Gilmore was executed by firing squad in Utah.

Constitutionally speaking, it was neither cruel nor unusual to shoot, hang, electrocute, or gas convicted criminals to death, but the gory nature of executions led to calls for something more humane. In 1977—the same year Gary Gilmore was tied to a chair and shot to death by local police officers behind an abandoned prison cannery—Oklahoma became the first jurisdiction in the world to approve execution by lethal injection. In 1982, Charles Brooks was the first convict to die that way.

On July 11, 1979, gangsters from Columbian cocaine cartels engaged in a brazen daylight shootout at a mall in Miami, which had become the cocaine import capital of America. The so-called "Cocaine Cowboys" incident made it clear that a new and ruthless breed of criminals without borders was at work in the United States. Local police were unprepared and outgunned, and a supersized federal law enforcement response soon descended on South Florida and its overseas cocaine suppliers.

The 1984 Comprehensive Crime Control Act eliminated parole in the federal system and established mandatory minimum-sentencing guidelines. Harsh sentences with no consideration of mitigating factors escalated the already stark rise in America’s prison population that began in the 1970s. Incarceration rates soared from 100 per 100,000 residents in the middle of the 20th century to 760 per 100,000 at its peak in 2008.

The emergence of DNA forensics gave investigators on both sides of the criminal justice system a powerful new tool. DNA evidence has helped secure countless criminal convictions and also helps organizations like the Innocence Project secure the release of the many people who are wrongly convicted.

By the late 1980s, the drug war had swelled America’s prison population to unprecedented levels—a cartoonishly disproportionate number of inmates were Black or Latino, and virtually all of them were poor. In response to the crack epidemic, new legislation mandated long, harsh prison sentences for even simple possession of crack, even if there was no intent to distribute. Penalties for the powder cocaine that white suburban users tended to prefer were not enhanced.

In 1991, a group of white Los Angeles police officers were videotaped brutally beating motorist and criminal suspect Rodney King in footage that quickly spread around the country and the world. For many poor minorities in L.A., the images were nothing new—but now that mainstream America could see it with their own eyes, change for the better seemed within reach. Their acquittal the following year triggered nationwide outrage and an explosion of long-simmering anger that sparked the 1992 Los Angeles Riots.

In 1992, federal law enforcement officers engaged in an 11-day siege at the remote Idaho home of a wanted man named Randy Weaver in an incident known as Ruby Ridge. Several people were killed in the standoff, including a U.S. Marshal and Weaver's wife and young son. The incident inspired radical, violent, and often heavily armed anti-government militants to unify in what would become the American militia movement.

Less than a year after Ruby Ridge, federal law enforcement once again found itself in a tense standoff with heavily armed radicals who didn’t recognize the authority of the federal government. The siege at David Koresh’s Branch Davidian compound in Waco, Texas, started with a deadly gunfight and ended with a fire that killed dozens of Branch Davidians, including children and pregnant women.

So-called “three strikes” laws were yet another heavy-handed response to soaring crime rates with designs to keep career criminals off the streets. Many low-level offenders, however, received life sentences for relatively minor crimes because they’d had previous trips through the system. The Violent Crime Control and Law Enforcement Act of 1994 extended the three-strikes policy to the federal system.

On April 19, 1995, a baby-faced white military veteran named Timothy McVeigh planted a truck bomb at the Alfred P. Murrah Federal Building in Oklahoma City. The blast destroyed the building and killed 168 people, including 19 children, in the worst domestic terrorist attack to that point in American history. Citing Ruby Ridge and Waco as his inspiration, McVeigh represented a new brand of white, homegrown, anti-government terrorism that continues to grow to this day.

On Jan. 25, 1996, Delaware added another gory record to criminal justice history. That day, a convicted murderer named Billy Bailey had his sentence of being “hanged by the neck until dead” carried out in front of an audience. It was the last execution by hanging in American history.

Civil asset forfeiture is the antithesis of the most basic protection of the American justice system: due process. The system allows law enforcement to seize money, cars, jewelry, and other property on the mere suspicion that it was gained through criminality without probable cause or a warrant. The system—which moves the burden of proof from the state to the accused—netted law enforcement $29 billion between 2000-2014 alone.

Thousands of civilians and 72 police officers were killed in the terrorist attacks of Sept. 11, 2001, and 71 of them died inside the World Trade Center. It was the deadliest day in the history of American law enforcement.

In 2002, the Supreme Court ruled in Atkins v. Virginia that it was unconstitutional to execute people with intellectual disabilities on the grounds that it constituted cruel and unusual punishment. The states, however, were left to determine who exactly qualified as intellectually disabled.

In the 2014 Riley v. California case, the Supreme Court ruled that warrantless searches of digital devices like smartphones during arrests were unconstitutional. Since today’s devices now contain personal and private information like the kind specifically mentioned in the Fourth Amendment, scrolling through a suspect’s phone was not the same as searching his pockets or car.

Many cities are now experimenting with alternatives to a bail system that keeps poor people in jail while awaiting trial but allows the more affluent to go free until their court dates arrive. About 500,000 people are currently awaiting trial in jail—most for low-level offenses—simply because they can’t afford bail. All of them are presumed innocent.

Reforms have put an end to convict leasing, chain gangs, and slave plantations dressed up as prisons, but the legacy of the 13th Amendment is alive and well. Most prisons still rely on inmate labor to function and—as authorized by the 13th Amendment—work is usually compulsory. Inmate labor is now coerced mostly through the threat of lost privileges instead of the whip, but prison workers still have virtually no rights or protections and, as of 2017, earned between 86 cents and $3.45 per day.