Editor’s Note (June 27, 2018): Scientific American is re-posting the following article, originally published on June 14, 2017, in light of the U.S. Supreme Court’s 5–4 decision to uphold the Trump administration’s travel ban, which blocks travelers entering the U.S. from several majority-Muslim countries.

The initial Executive Order signed by President Trump was widely criticized for being anti-Muslim and unconstitutional, and several courts agreed. Hints of the revised order the Administration is planning suggest not much will change. Both are based on nothing more than flawed data, and demonstrate our disconnection with our dirty past with immigration.

The restrictions of 1924 The Johnson-Reed Act were sold to the public as a critical national security measure. The law banned individuals from a defined geographic region from entering the United States and empowered immigration officials to deny entry to any immigrant. The ban also broke ground for further, more restrictive immigration quotas. As he signed the bill, President Calvin Coolidge declared "America must be kept American."

Included in this legislation was extreme vetting procedures based on flawed data that resulted in the death of Jewish refugees. The Johnson-Reed Act had its roots in the scientifically discredited concept of biological determinism, which claims biology alone can explain the social and economic disparities between groups of people (e.g. races or sexes).

As a biological anthropologist, it is a particularly raw, troubling, and complex subject due to the role social scientists played in supporting and advancing it.

Early anthropologists were obsessed with measuring bodies - head shape, brain size, body size, etc. They linked any physical differences with cultural or social stereotypes. For example, average cranial capacity was used to justify intelligence inferiority of Africans and aboriginal Americans. The faulty assumption being that intelligence is determined by one measurable trait - the size of your brain. (Before you argue this point, know that Neandertals had bigger brains than us.)

The United States rallied behind this idea and used culturally "objectionable" behavior (e.g. prostitution, addictions, criminal activity) as an indication of inherited mental deficiency. These mental deficiencies were based on intelligence tests that were designed to gauge little more than familiarity with American culture such as asking immigrants to identify the use of Crisco. This flawed test was taken to Ellis Island and any immigrants traveling third class became the first target.

This "extreme vetting" peaked with the testing of 1.75 million World War I Army recruits that only succeeded in collecting more flawed data. Scores were used to rank immigrant recruits by their country of origin, with those from southern and eastern Europe deemed "inferior stock.”

These statistics were used as political propaganda to instill doubt in the future of United States democracy. Involvement in World War I only increased public support for immigration restrictions. Deportations increased, immigration admissions declined, and Congress worked to ban those that would make America weak. The result was a complete ban of anyone from the "Asiatic Barred Zone" in 1917. Immigration quotas were implemented shortly after, and continued to become more restrictive with the Johnson-Reed Act. Immigration from southern and eastern Europe was severely impacted.

During the 1930s, Jewish refugees attempting to flee Europe were turned away at the U.S. border. Extreme vetting based on flawed data allowed this to happen, and history is repeating itself. The initial executive order temporarily banning immigration from seven predominantly Muslim countries and indefinitely suspending Syrian refugee immigration, too, was based on little more than flawed data. The ban was meant "to protect the American people from terrorist attacks by foreign nationals admitted to the United States."

However, risk analysis indicates that homegrown, right-wing extremists pose a bigger threat to our nation's security and safety than Muslims. Not one Muslim refugee has carried out a major terrorist attack in the United States. Those individuals who have been implicated were from countries not included in the order. In short, the connection between violence and Islam is as flawed as the idea that a big brain means you're smart.

The executive order has been ruled unconstitutional, but this isn't the end of it. The Trump Administration has promised to issue a revised executive order. "Extreme vetting will be put in place," Trump said. Considering the already tremendously thorough process already in place, it makes one question how extreme it will get.

What does this mean for Syrian refugees? Civil war has displaced an estimated 11 million Syrians, with one million seeking refugee status in Europe alone. To be sure, there are those who say that European countries can handle this crisis, and many have granted asylum to hundreds of thousands of people, but they can't handle this large a migration without help. This displacement is the largest crisis of its kind to face our world.

These refugees include men, women, and children who have endured the psychological and physical trauma of war; yet, our borders are indefinitely closed to them. To that end, take community-based and government-based action. Reach out to your local mosque and plan an interfaith gathering or march in your community. Contact your representatives and let them know you oppose ill-informed immigration policy.

We have a responsibility to take the tired, the poor, and huddled masses yearning to breathe free. We cannot make the same grave mistakes we made in our past.