In his 2018 State of the Union speech, Donald Trump repeatedly referenced a specific gang, MS-13, by name. These mentions were intended to justify his administration’s anti-immigration policies. Though MS-13 originated among Salvadoran immigrant communities in L.A., most of its members are now concentrated in Central America, particularly El Salvador. The group is relatively small: Of the 1.4 million gang members the FBI estimates are in the U.S., less than one percent of them belong to MS-13.

To most Americans, it makes sense that the federal government might target a large organization that commits crimes nationally. But before Robert F. Kennedy’s term as Attorney General from 1961 to ‘63, the federal government—as well as many Americans—didn’t really understand the concept of “organized crime.”

When Kennedy arrived at the Department of Justice, its organized crime and racketeering section “was just two or three lawyers reading files,” says Ronald Goldfarb, a lawyer who worked in the section under Kennedy and wrote a book about the subject titled Perfect Villains, Imperfect Heroes. “[Kennedy] enlivened it so that it quickly grew to about 60 lawyers, and it was the department’s priority.”

Admittedly, Kennedy only gained control of the DOJ because his older brother, John F. Kennedy, was president. At 35 years old, Robert Kennedy had no experience for the job, and JFK acknowledged this by saying that his brother “needs some solid legal experience and this job should provide it.” (Goldfarb says the quip is an example of JFK’s wry humor, but it was also kind of true.)

Despite his lack of experience, Goldfarb maintains that Robert Kennedy rose to the occasion. Under Kennedy, one of the DOJ’s main focuses became the Mafia, which by the mid-20th century had an estimated 5,000 members and thousands of associates across the country. Previously, individual gang members had been investigated for crimes, but this was the first time the government had attempted to take on a whole criminal organization.

Kennedy was the first Attorney General to encourage the government’s investigative agencies—the DOJ, the FBI, the IRS and others— to work together to investigate large-scale crimes and national crime syndicates.

The department also investigated crooked unions, gambling rings, and other organizations that broke laws in multiple parts of the country. In 1961, Kennedy sent Goldfarb and others to Newport, Kentucky, with instructions to look into a lurid case. When a man named George Ratterman ran for sheriff of Newport’s county of Campbell on a platform of tackling the city’s rampant crime, his opponents drugged him and planted him in bed with a stripper named April Flowers to discredit him.

Known as “Sin City”, Newport was then a hub for prostitution and the center of a national gambling ring, where a betting syndicate handled “over the wires, extraordinary sums of money bet around the country,” Goldfarb writes in his book. In the end, Ratterman won the sheriff’s seat and crime began to go down.

“Robert Kennedy, when he went to testify before Congress, used Newport as an example of why it was a myth to consider crime as local,” Goldfarb says. “Because much of organized crime was interstate.”

Kennedy also had to push past resistance from FBI Director J. Edgar Hoover, who at the time spoke and behaved as if he didn’t believe the Mafia existed. It’s not clear if Hoover really believed that; but in any case, Goldfarb says Hoover had other reasons for avoiding organized crime.

“He was so powerful in those days that he resented being subjected to the controls of the Attorney General,” Goldfarb says. “He was more interested in catching communists in those days. He was interested in bank robberies, auto thefts, things where the media made him look good when he went up to Congress for money.”

In contrast, Goldfarb says “our cases would take years to develop and tremendous resources, so [Hoover] was very, very reluctant to do what RFK wanted him to do.” Even so, under Kennedy’s leadership, the DOJ began to work with the FBI to investigate organized crime.

Because of Kennedy’s contributions, the federal government came to understand that sometimes crime in different parts of the country is connected—a concept that, in the era of cyberhackers, seems obvious.

But distinguishing valid international organizations from the political scapegoats? That’s the part of organized crime that modern America is still struggling with.