Donald Trump has, throughout his presidency, used the American immigration system’s alleged vulnerability to terrorist infiltration as a justification for his harsh restrictions on immigration.

“America must fix its lax immigration system, which allows far too many dangerous, inadequately vetted people to access our country,” Trump said in one representative statement. “The terrible harm that this flawed system inflicts on America’s security and economy has long been clear.”

But Trump’s claims that our immigration system is “lax” aren’t true — or, in fact, even close to true. A new study from David Bier, an immigration policy analyst at the libertarian Cato Institute, digs into the data on just how many terrorists America has let into the country.

He found that only a single terrorist who committed a deadly attack snuck through the vetting process to enter the US legally after 9/11, out of a total of 379 million people who lawfully entered the country. Between 2002 and 2016, roughly twice as many people were killed by their own kitchen appliances than by a terrorist who slipped through the immigration system.

Trump’s fearmongering bears absolutely no relation to reality.

What the study found

Cards on the table: Cato is a pro-immigration think tank. But a close look at Bier’s methodology suggests that it’s solid; in fact, it’s actually likely to produce an overestimate of the US immigration system’s terrorism problem than an underestimate.

Bier combed through government data on terrorism prosecutions and terrorists killed by law enforcement in the midst of a terrorist act. He also combed through several nongovernment databases on terrorism to make sure he wasn’t leaving any incidents out.

Bier then looked for what he calls “vetting failures,” which he defines as cases where “a foreigner is granted entry to the United States who had terrorist associations or sympathies and who later committed a terrorism offense.” That’s designed to get to the crux of the debate Trump is raising: Is the United States, in fact, admitting “dangerous, inadequately vetted” individuals — or is the system mostly screening them out?

Identifying vetting failures is hard to figure out, obviously, as we can’t really be sure what was in someone’s mind when they entered the US (with a few exceptions, like the 9/11 hijackers, who were part of pre-organized plans). So the Cato study makes a pretty broad assumption: that anyone who entered the United States when they were a) 16 or older and b) committed a terrorism-related offense within 10 years of entering the US counts as a “vetting failure.”

This figure is probably an overcount; it’s easy to imagine someone coming into the US on, say, a student visa and then becoming radicalized a year or two into their time in America. But it’s a fine proxy for a study that bends over backward to be generous to Trump’s argument.

Bier found that, between 1986 and 2001, there were 52 vetting failures — a rate of about one vetting failure for every 4.7 million grants of entry. The most notorious of such failures were the 9/11 hijackers themselves, who took advantage of the fact that State Department visa officers had zero training in identifying terrorists during interviews as well no access to law enforcement files on suspected terrorists.

After 9/11, the US conducted a massive overhaul of its visa screening procedures — retraining visa officers, strengthening databases on terrorism suspects, and adding biometric information (like fingerprints) to keep people from simply lying about whether they’d been denied a visa under another name. The result was a massive decline in vetting failure rate; between 2002 and 2016, there were a total 13 people who qualified as vetting failures; a rate of one failure for every 29 million admissions.

But it goes further than that. The goal of these reforms was to prevent another 9/11, an attack orchestrated from outside the country, in which attackers sneak through the immigration system to conduct a massive, planned assault. No such attack has happened since; in vetting failures since 9/11, all but one of those let through were convicted on terrorism-related charges, like providing money to a terrorist group, rather than themselves killing anyone in an attack.

The only person to fit Bier’s “vetting failure” criteria and commit a deadly attack was San Bernardino shooter Tashfeen Malik, who had committed no crimes prior to her entry to the United States but had expressed sympathies for jihadist groups in social media posts. Malik and her husband, American citizen Syed Rizwan Farook, went on to kill 14 people in their 2015 attack on a California nonprofit that serves people with disabilities.

That means that flaws in the US immigration and visa system have contributed to a total of 14 deaths during the period studied by Bier (and it’s worth noting the US introduced social media screening after the San Bernardino attack). This is despite admitting about 379 million people during that timeframe, an astonishingly low rate of failure.

Why this matters

To put this in perspective, I looked at the Centers for Disease Control database on deaths in America, oddly called WONDER, and pulled a few examples of things that had killed more Americans between 2002 and 2016 than vetting failures:

37 died from “contact with hot household appliances,” like stovetops and ovens.

34 died from their own pajamas burning (“exposure to ignition or melting of nightwear,” as WONDER puts it).

20 people died in hot air balloon accidents.

16 people were killed due to “contact with steam or other hot vapors.”

This isn’t to minimize the horror of any death; every life lost is a tragedy. Rather, it’s to point out the yawning gulf between the scale of the immigrant terrorist problem and the president’s extreme proposed solutions, like a ban on Muslims entering the United States.

Trump has not called for discriminating against hot air balloon enthusiasts or a war on exploding nightwear, because that would be self-evidently ridiculous. But he is hyping up fears of the immigration system admitting terrorists — an extremely rare event, significantly less common than a person being killed by an oven or stovetop — to justify policies that would discriminate against literally millions of people.

The president wants you to believe that it’s easy for terrorists to flood into the United States under current law, that we are at serious risk unless we take the extreme step of barring huge numbers of people, mostly from Muslim-majority countries, from entering the country.

You simply have no reason to believe him.