IN LATE July Donald Trump travelled to Suffolk County, a suburban area of New York wracked by violence from MS-13, a criminal gang with a large presence in the United States and Central America. Speaking to law enforcement, the president called the gang members “animals”, rapists and robbers who butchered children. Mr Trump argues that weak border enforcement during the Obama administration emboldened the gangs, using the example of MS-13 to drive home the need for stricter immigration policies. Yet his tough talk may inadvertently be helping the gang. How?

MS-13 is largely composed of El Salvadorian and Central American immigrants; some of them are undocumented. It was born in the 1980s in Los Angeles when hundreds of thousands of people fled to the United States to escape civil war in El Salvador. To find a sense of community in their new home and protect themselves against the Mexican street gangs that already dominated the city’s barrios, they formed what was then called the Mara Salvatrucha Stoners. It began as a social group but progressively grew more violent. Beginning in the 1990s, deportations extended the gang’s influence to El Salvador and its neighbours, which now have some of the highest murder rates in the world—in part because MS-13 operates there. In certain parts of America, the gang has recently become more of a threat again. Its members have killed 17 people in Suffolk County alone since January 2016, often with machetes and wooden clubs.

It is not entirely clear why the violence is escalating again. But Mr Trump’s tough talk about the gang might make matters worse in two ways. Unlike drug cartels, which strive to operate in the shadows, criminal street gangs often relish publicity. MS-13, whose members often use knives and machetes instead of guns to kill rivals, wants to be perceived as brutal and brazen. By projecting that image of the gang himself, Mr Trump may be inadvertently empowering MS-13 and helping them recruit. To make matters worse, his harsh anti-immigration rhetoric seems to be having a chilling effect on crime reporting in immigrant communities. This matters because MS-13 usually preys on the vulnerable, who are often immigrants. To get at the gang, police need their cooperation: during a recent bust of 21 MS-13 members in Los Angeles, the police chief was quick to acknowledge that the investigation was greatly aided by witnesses who were illegal immigrants.

But it looks as though immigrants are increasingly wary of reporting gang-related crime to the police. In the first quarter of 2017, reports of sexual assault by Los Angeles’ Latino population plummeted by 25%. Similar drops occurred in Denver, Houston and Philadelphia. Officials put this trend down to people’s heightened fear of deportation. If he continues to talk tough, Mr Trump may end up making MS-13 both stronger and harder to prosecute.