The Supreme Court, in a ruling released on Monday, temporarily reinstated a portion of President Trump’s executive order banning people from six Muslim-majority countries from entering the United States.

Starting this Thursday, citizens of Iran, Libya, Somalia, Sudan, Syria, and Yemen will be banned from the United States unless they can demonstrate a “bona fide” relationship with American citizens or organizations. What qualifies as a “bona fide” relationship isn’t clear, but that’ll be the legal standard for admissions into the United States until the Supreme Court issues a final ruling on the constitutional merits of the entire executive order.

It’s hard to say how the legal case will shape up. But as the Court deliberates, it’s worth noting that the policy justification for this ban — terrorism — is complete hogwash.

No person from the six targeted countries has committed a deadly terrorist attack inside US borders. The Trump administration has not offered any compelling reason to believe that citizens of those countries pose any kind of special terrorist threat going forward. The odds of being killed by an immigrant terrorist of any kind, let alone a Muslim immigrant, are one in 3.6 million.

Former New York mayor Rudy Giuliani, of all people, admitted the real thinking behind the ban. In a January interview, he said that the president had asked him and others about how to do a ban on Muslim immigration “legally” — and that this ban was the result of that process. It all goes back to what President Trump said back in December 2015 when he first announced the ban proposal: that the US needed “a total and complete shutdown of Muslims entering the United States” because there is “great hatred towards Americans” among Muslims.

The thinking here is quite clear — Muslims are an enormous threat to American lives, and that the federal government needs to stop more Muslims from coming to the US by whatever means possible.

This is bigoted — and, according to the best data we have, empirically false. A January study from University of North Carolina-Chapel Hill sociologist Charles Kurzman that tallies up the data on terrorist attacks committed by Muslim Americans shows why.

The study found that only 46 Muslim Americans (defined in the study as “Muslims who lived in the US for an extended period”) were linked to violent extremism at home or abroad in 2016. The total Muslim American population is 3.3 million.

Of those 46, only 24 were actually implicated in a concrete terrorist plot; the others did things like attempting to travel to Syria to join ISIS. Those plots claimed 54 lives, the vast majority of which (49) came in a single attack — the Pulse nightclub shooting in Orlando. Kurzman also looked specifically at immigrants and Muslims whose families hail from the countries targeted travel ban — and, you guessed it, found no special propensity for terrorism.

The study isn’t making an apples-to-apples comparison; the more directly relevant statistic would look at whether or not Muslim Americans kill more US citizens here than any other specific political or religious group (other research has looked at that question). But Kurzman’s work vividly underscores a simple fact: Muslim Americans, in both raw terms and as a percentage of size of their total community, commit very small numbers of killings.

By contrast, roughly 11,000 Americans were killed in gun homicides in 2016 — yet Trump has never proposed banning guns.

“It is flatly untrue that America is deeply threatened by violent extremism by Muslim-Americans,” David Schanzer, director of the Triangle Center on Terrorism and Homeland Security, said in a statement accompanying the study’s release in January. “Attacks by Muslims accounted for only one third of one percent of all murders in America last year.”

Trump’s travel ban is not a serious counterterrorism proposal

Kurzman has been conducting a version of this study every year for the past eight years, in order to get a comprehensive sense of whether jihadist movements are successfully recruiting among Muslim Americans. He found a small increase in extremist activity 2015, in the wake of ISIS’s stunning military victories the prior year, which declined in 2016.

Overall, for as long as Kurzman has done the study, the number of actual terrorist attacks committed by Muslim Americans has been exceptionally small.

“The 54 fatalities caused by Muslim-American extremists in 2016 brought the total since 9/11 to 123,” Kurzman writes. “More than 240,000 Americans were murdered over the same period.”

This year, Kurzman did something new. In light of the travel ban, Kurzman tried to figure out whether immigration from these countries, specifically, posed an special terrorist threat.

It didn’t. Muslim Americans with a background from these countries were not well-represented among the (very small) ranks of Muslim American terrorists.

“Since 9/11, only 23 percent of Muslim-Americans involved with violent extremist plots had family backgrounds in [targeted] countries,” Kurzman writes. “There have been no fatalities in the United States caused by extremists with family backgrounds in these countries.”

Immigrants of all kinds were actually underrepresented in the ranks of Muslims attracted to extremism. The following charts show the percentage of Muslim Americans from different backgrounds, on the left, and the percentage of Muslim Americans attracted to extremism from each of these backgrounds, on the right. Immigrants are clearly underrepresented:

The only overrepresented group, you’ll note, are converts — people from non-Muslim backgrounds. Many of these people are likely attracted to extremism rather than Islam per se, as you can see by looking at the rates of violent extremism among non-Muslim groups.

“Between 2001 and 2015, more Americans were killed by homegrown right-wing extremists than by Islamist terrorists,” my colleague Jennifer Williams writes. “Adopting extremist views and committing horrendous acts of violence in the name of some ‘righteous’ cause, be it religion or politics or just plain old hatred, isn't something that only Muslims, or Arabs, or immigrants do.”

Correction: This post originally described Charles Kurzman as being affiliated with Duke University. While his report was published by the Triangle Center on Terrorism and Homeland Security, which is based at Duke, Kurzman himself teaches at the University of North Carolina-Chapel Hill.