'Why are Americans so scared of Syrian refugees?'

People in the US want to shut the door on Syrian refugees. According to one poll, 53 percent of Americans disapprove of allowing them into the country while another 11 percent would admit only Syrians who are Christians.

Most governors have said that they will not allow Syrian refugees into their states (though they have no legal authority to block them), and now Congress has gotten into the act. By a vote of 289–137, the House passed a bill that would impose substantial hurdles on further refugee settlement.

The liberal commentariat has gone berserk, accusing opponents of nativism and xenophobia. The criteria used to admit refugees are strict, so the risk that any of them will commit crimes is very low. As Alex Nowrasteh points out, almost 1 million refugees have been admitted into the United States since 2001, and none of them has successfully carried out a terrorist attack. Moreover, given the infinitesimal number of Syrian refugees to be let into the country out of the millions of people who would qualify, it would be crazy for a professional terrorist to try to enter this country by pretending to be a refugee. It would be easier to obtain a tourist visa.

A number of factors predict when people place excessive weight on a low risk.

So why the hysteria? While there are plenty of nativists in the country, nativism is not the whole story. Most Americans are not nativists - the country has welcomed millions of refugees and other immigrants. The explanation for the public’s reaction lies elsewhere.

Overreaction to tiny but frightening risks is not a new problem. Americans fear flying much more than driving, even though flying is much safer. Yet the fear of flying has led to massive - probably excessive - public investment in airplane safety while investment in auto safety has languished.

Other famous public overreactions, described by Cass Sunstein and Richard Zeckhauser in a recent paper, include the reaction to Love Canal (no evidence of adverse effects), the pesticide Alar (risk of cancer extremely unlikely), shark attacks (hardly ever happen), and the anthrax attack in 2001 (five deaths). Genetically modified organisms and vaccines also terrify some people, despite abundant evidence that both are safe. People vastly overestimate the risk to health and safety of particular threats, leading the government to squander resources eliminating tiny risks while the significant threats (heart disease, car accidents) go unaddressed.

Psychologists who have studied these reactions have identified a number of factors that predict when people place excessive weight on a low risk. All of these factors point, with remarkable clarity, to the reaction to the Syrian refugee crisis.

People underestimate risks that are familiar, under their personal control, voluntarily incurred, ignored by the media, and well-understood. Driving an automobile is the best example. Everyone is accustomed to driving, feels in control of the car, and drives by choice. The extraordinarily high risk of an accident becomes background noise that no one pays attention to. By contrast, the opposite qualities are true for the risks that people fear the most, like meltdowns of nuclear reactors, airplane crashes, and cancer-causing food additives - and even more so for terrorism. The Syrian refugees are strangers from an unfamiliar and terrifying part of the world, and they will be placed in neighbourhoods where people did not necessarily invite them in. The media has made much of them, particularly after the Paris attacks, and most Americans don’t understand the circumstances that drove them from their country.

People also overreact to risks that may produce especially dreaded or gruesome outcomes. While a car accident can produce mangled bodies, a terrorist attack is an especially gruesome event, often involving hostage-taking and terrifying helplessness.

Terrorist attacks victimise children as well as adults, and there is no practical way to avoid them. People are more likely to tolerate risks when the accompanying benefits are clear - that’s why, in the end, people fly. But any benefits from refugee resettlement are remote, intangible, and indirect. People also fear risks of human origin (vaccines) more than risks of natural origin (the flu), and terrorism is very much the fruit of human ingenuity.

A final consideration is trust in government. People put up with risks if they trust the institutions that manage them. Air safety regulators have earned our trust, as have the various regulators with authority over automobiles, roads, and accidents (whether they deserve our trust or not).

But while most Americans trust the government to protect them from terrorism, that confidence has been eroding. President Obama deserves some blame. Shortly before the Paris massacre, he said that ISIS had been “contained,” and his response to the attack has been less than forceful. Not surprisingly, opponents of refugee admission claim that the government cannot be trusted to properly vet applicants. Whether or not this argument is fair, it feeds into public anxiety.

Obama has also done a poor job of reacting to this anxiety. He has taken the easy route of accusing opponents of bigotry by noting that some politicians want to allow Christian Syrians into the country while blocking Muslims. The better response would be to figure out a way to persuade Americans that the risks posed by the refugees of both types are minimal.

*Eric Posner, a professor at the University of Chicago Law School, is author of The Twilight of International Human Rights Law.