Donald Trump has promised to make the United States more secure by expelling immigrants and restricting their entry into the country, citing what he says are alarming crime statistics.
But a study published this week that analyzes 20 years of research on the impact of immigrants in specific neighborhoods and cities, found that there is no relationship between immigration and crime.
The authors, Charis E. Kubrin of the University of California, Irvine, and Graham Ousey of the College of William and Mary examined findings from more than 50 studies between 1994 and 2014 in what is known as a meta-analysis, a study of all studies in a field of research. This is the first time that such an analysis has been carried out in the field of criminality of immigrants.
Kubrin told Univision News that they found that more immigration usually means less crime. Only a very small number of studies found that immigration was more criminal.
"As far as I'm concerned the case is closed on the issue of whether immigration is causing more crime," Kubrin said. "The criminologists are turning the page but the rest of the country is still asking the damn question."
The study comes as Republicans are pushing legislation, known as Kate's Law, to increase penalties on undocumented immigrants who re-entering the country and commit crimes after having been deported. The law takes its name from Kate Steinle, killed in San Francisco two years ago after being shot by an undocumented immigrant who had been deported five times.
The analysis of Kubrin and Ousey confirms the intuition of many criminologists who have looked at trends in the United States during periods of more permissive immigration policy.
In the 1970s and 1980s, U.S. cities were struggling with a mix of drugs, homicides, robberies, racial riots and New York was staring at bankruptcy.
Despite pessimistic forecasts, the early 1990s brought a steep decline in violence and urban revitalization. While the murders in New York hit 2,200 in 1990, last year there were only 335, according to the police department. A similar decrease can be observed at the national level, although in some large cities there has been a rebound recently.
Over that same time period immigration has accelerated and, consequently, the proportional weight of foreigners in the total population of the United States. In 1970, in the middle of the crime crisis, the number of people in the US who were born abroad was 9.6 million - 4.7% of the total. By 2015, the foreign population had grown to 43.3 million - or 13.5%.
That rapid growth in the number of foreigners was a consequence of the immigration law of 1965 which eliminated the restrictive migrant quotas by countries that had been in force since the 1920s.
Ambitious and hardworking
Although foreigners are generally subject to more adverse conditions, they are less prone to crime and other forms of social behavior, for example drug consumption.
This could be explained by the fact that the immigrants who arrive in the US are usually ambitious individuals, very motivated to progress. According to this thesis, it does not make sense for immigrants to jeopardize their new lives by behaving antisocially.
The beneficial effect of immigrants can be observed via the "broken windows" thesis that abandoned buildings are a sign of urban decay. Immigrantion advocates argue the new arrivals contribute to urban revitalization in many areas, including the Rust Belt, partly because they occupy these abandoned homes.
Other recent studies, such as The Sentencing Project's Immigration of Public Safety, have shown that immigrants commit less crimes than those born in the United States.
Criminologists are frustrated by the persistence of the immigrant criminal myth. Two decades of studies have not served to curb the advance of anti-immigration propaganda.
"It's very difficult to fight stereotypes," said Ramiro Martinez, a criminologist at Northeastern University In 1996, Martinez was one of the first criminologists to study the impact of immigrants on crime.
"Through the many studies we have done over the years, people still have more confidence in the strident statements about immigrants," Martinez laments.
The current conflict between the perception of immigrants and objective data has its precedent in the first decades of the twentieth century. At that time, government commissions showed that there was no link between immigrants and increased crime. This did not prevent the rise of nativism and restrictive legislation on the arrival of foreigners.
If Trump reduces the number of immigrants the research findings suggest it could have the counterproductive effect of a rise in crime? Criminologists prefer to be cautious since the causality of immigration on crime is so weak.
"What is certain is that a significant decline in immigration could mean a stagnation in the revitalization of many cities, which could increase the likelihood of crime rising," says Harvard professor Sampson.
What few criminologists have doubts about is that if immigration falls during Trump's presidency, there is no guarantee that it will make the US a safer place.
"All the things he is doing about immigration are completely unnecessary at best, and very harmful at worst," says Kubrin.