President Trump flew to New York Friday to talk about “liberating” Long Island from MS-13. Trump has often used the gang, its bloody tactics, and its ties to Central America to push his immigration policies, and the picture he painted Friday was one of Long Island as a war zone.

MS-13, Trump said, has “transformed peaceful parks and beautiful, quiet neighborhoods into blood-stained killing fields.” He said the gang members “stomp on their victims,” “slash at them with machetes,” and stab them with knives. To “every gang member and criminal alien,” Trump threatened, “we will find you, arrest you, we will jail you, and we will deport you.”

In the past 18 months, the gang has been implicated in 17 murders in Long Island. It’s also made gory headlines in Maryland and Northern Virginia, all of which are home to large Central American populations. But while MS-13 is indeed dangerous, as I wrote last month, law enforcement often disagrees with the president on how the gang should be handled. In the United States, MS-13 is seen largely as a domestic law-and-order issue, like other gangs are—and one that deportation won’t solve.

It’s also unclear if the gang, which originated in Los Angeles some 30 years ago, has grown nationally, or if it has become more violent recently. Data are either old or kept at a jurisdictional level. This makes it hard to quantify how MS-13 has changed, and it leaves people susceptible to headlines and anecdotes. For instance, law-enforcement officials in Long Island’s Suffolk and Nassau counties have said crime as a whole—including murder, rape, and robbery—is down. But the stories describing MS-13 killings have nevertheless provided Trump a perfect bogeyman, one his administration has been willing to capitalize on to help push its immigration agenda here and abroad.

While Trump was describing Long Island as a blood-drenched combat zone, Attorney General Jeff Sessions was in El Salvador, where he congratulated his counterpart, Douglas Melendez, on the arrest of about 700 gang members in the past two days. MS-13 was founded in Los Angeles by young Salvadoran migrants, but in the 1990s the United States deported tens of thousands of undocumented gang members back to Central America. There are now believed to be more than 70,000 members in Central American countries like Honduras, Guatemala, and El Salvador. The Trump administration hasn’t detailed its approach to gang violence in the area, but by Sessions offering such strong congratulations on jailing gang members, it’s likely it will push for a hard-line approach.

In El Salvador, a policy of mass arrests, raids, and packed prisons is called “mano dura”—or strong hand—and it has been used for decades to little success. Copying the strategy in Los Angeles, in the early 2000s El Salvador cracked down on the gangs, but the murder rate spiked as MS-13 fought with rival gangs. In 2012, the government tried a different approach, using the Catholic Church to mediate a truce. But three years ago when the country’s current president, Salvador Sánchez Cerén, took office, he instead doubled down on mano dura, and in 2015 murders peaked to their highest since the civil war. What critics find lacking in a strictly hard-line approach is that MS-13 took hold because of El Salvador’s weak institutions. Focusing only on arrests ignores the larger systemic issues, like the poor economy, educational system, and corrupted judicial system.

The Trump administration’s proposed budget cuts to the U.S. State Department would slash aid to Central America by 39 percent, starving both community-based programs and funding for “hard-side” counter-drug programs that support law enforcement. Congress has pushed back on the proposed cuts, and there’s strong bipartisan support for aid to Central America, so it’s likely the aid will largely remain.

“I mean, I guess like with anything in this administration we have to see how it plays out in practice,” Sarah Kinosian, a program officer for citizen security at the Washington Office on Latin America, told me, referring to the administration’s approach. Kinosian said the fact that the Trump administration wants to work with El Salvador is positive, because cooperation has proved helpful in the past. Ten years ago, the FBI set up a program in El Salvador that helps train local investigators and allows agents to coordinate internationally. It worked well enough that the FBI recently expanded the program to Honduras and Guatemala. But enforcement-only isn’t a long-term fix, Kinosian said, and neither is a deportation-only strategy.

In El Salvador, political leaders have held emergency meetings to discuss what they will do if the Trump administration follows through with its promise of mass deportations. “Probably we won’t feel the symptoms today or tomorrow or the next week,” San Salvador Mayor Nayib Bukele told The Washington Post in May. “But probably in six months or a year we’ll be feeling the symptoms … ”

If that does happen, it could very well destabilize the country more and lead to increased migration to the United States. Trump, then, will have undermined his own strategy.