How likely are foreign terrorists to kill Americans? The odds may surprise you
attacker terrorist gun assault rifle grenade launcher pointed toward camera shutterstock_2986132
attacker terrorist gun assault rifle grenade launcher pointed toward camera shutterstock_2986132

(Shutterstock)

The idea that foreign terrorists pose a grave threat to Americans is sacrosanct to President Donald Trump's immigration ban, which he enacted on Friday.

Trump's executive order immediately barred about 220 million people from seven majority-Muslim nations from setting foot on US soil for the next few months. It also triggered nationwide and international protest, sowed confusion at airports, and attracted judicial challenges (and defeats), among other discord. Military and foreign policy experts, meanwhile, expressed concern the ban may actually worsen the threat of terrorism.

The president, his administration, and his supporters defended the executive order by underscoring how the measure aims to protect US citizens from foreign-born terrorism.

"We cannot gamble with American lives," Department of Homeland Security (DHS) secretary John Kelly said Tuesday during a televised press conference. "I will not gamble with American lives."

But how justified is that gamble, according to real-world data?

president donald trump signs immigration travel ban executive order pentagon jan 27 207 reuters RTSXPZ8
president donald trump signs immigration travel ban executive order pentagon jan 27 207 reuters RTSXPZ8

(President Trump signs an executive order on January 27, 2017.Carlos Barria/Reuters)

According to a September 2016 study by Alex Nowrasteh at the Cato Institute, a libertarian think tank, some 3,024 Americans died from 1975 through 2015 due to foreign-born terrorism. That number includes the 9/11 terrorist attacks (2,983 people) and averages nearly 74 Americans per year.

Since 9/11, however, foreign-born terrorists have killed roughly one American per year. Six Americans have died per year at the hands, guns, and bombs of Islamic terrorists (foreign and domestic).

"I once asked a guy at [the National Institutes of Health] how much we should spend on preventing a disease that kills 6 per year, and he looked at me like I was crazy," John Mueller, a foreign policy expert at the Ohio State University and co-author of the book "Chasing Ghosts: The Policing of Terrorism", told Business Insider in an email.

Here's how the lifetime odds of the most common — and feared — causes of death for Americans stack up against foreign killings (highlighted in red):

BI Graphics_Odds of Dying
BI Graphics_Odds of Dying

(Skye Gould/Business Insider)

Americans are more likely to win a lottery jackpot

The chart above doesn't account for an American person's specific behaviors, age, sex, location, or other factors that can wildly change up the results — it's one big, fat average of the US population.

The data primarily come from a 2016 report by the National Safety Council and the National Center for Health Statistics' final 2013 report on causes of death in the US, which was released in February 2016 (and is the most current).