“Give me your tired, your poor, Your huddled masses yearning to breathe free…” To these familiar words engraved on a plaque on the Statue of Liberty that express the compassion and tolerance of American society at its best, one might add: “Give us your inquisitive and creative minds, who aspire to truth and knowledge, Who we will weave into the fabric of our great universities.”

Opening America’s arms to immigrant populations and political refugees affirms it national ideals and compassion. That tolerance has also been instrumental in the ascent of the country’s university system to international preeminence. But while America is often spoken of as a “nation of immigrants,” it has not always welcomed immigrant groups with open arms or accepted them as “true” citizens during perceived perilous times. A prime example of the capacity for intolerance (and later admission of the shame of these actions) occurred 75 years ago when President Franklin D. Roosevelt signed Executive Order 9066, which led to the internment of up to 120,000 men, women, and children of Japanese origin after the outbreak of World War II. Their incarceration was based on fear, xenophobia, and racial prejudice. The order was upheld, of course, in the U.S. Supreme Court’s infamous Korematsu v. United States decision in 1944—a decision that has not to this day been overturned. Looking back, most people would concede that the order was a gross mistake—a stain on the integrity of American democracy.

Nonetheless, the willingness to assimilate foreigners into American society has been part of the nation’s strength—a productive force that has added vitality to a maturing culture. The same has been true of U.S. universities’ attitudes toward foreign faculty and students with talent. Now, with President Trump’s actions that stigmatize those who are foreign-born and limit immigration, in addition to his promise to deport millions of undocumented immigrants, universities and the nation are under threat. The history of the past 75 years suggests how important the contributions of immigrant scholars and students have been to the vitality of America’s universities.

For the first three decades of the 20th Century, German universities reigned supreme. They earned many Nobel Prizes in the years from its inception until 1933. American educational leaders traveled to Germany on fellowships either to observe the extraordinary research done at these universities or to enroll and earn degrees there. They brought back to the United States the idea of the German research university, and from the late 19th century, they wished to imitate and improve on many of its structures at institutions in the United States. With the rise to power of Hitler in January 1933, everything changed. As I wrote in my book, The Great American University, by April of that year, Hitler had purged the great German universities of their intellectual stars—either on religious or ideological grounds (about 25 percent of their pre-1933 physics community and fully 50 percent of their theoretical physicists emigrated, for example). The great intellectual migration to the United States and England began. It would be hard to overstate the significance of this irony: The tragedy of Europe had enormous positive consequences for American research universities.

Germany’s education system has never recovered. Once the best in the world, its institutions now make few appearances on lists of the top 50 universities. Just consider the all-star team of great minds that migrated to the United States from Germany, Austria, Hungary, and other nations threatened by National Socialism. As the Nobel Laureate and Columbia University physicist I.I. Rabi said, the young talent at American universities’ could match any in the world, but they lacked leadership. The great European intellectuals offered that leadership, and America’s universities took-off toward preeminence. It came from the likes of great physicists such as Albert Einstein, Leo Szilard, and the physicist-turned-molecular-biologist Max Delbruck. But there were also the Nobelists Hans Bethe, Enrico Fermi, as well as social scientists such as the great sociologists Paul Lazarsfeld and Theodor Adorno, and émigré artists, writers, and composers like Thomas Mann and Bela Bartok.

A new chemistry emerged at American universities. It merged the creative, vertically mobile Americans (many the children of immigrants) with the horizontal mobility of the émigré scholars. These immigrant scholars were followed by a “second wave” of brilliant minds. This group of some 100,000 children, as Gerhard Sonnert and Gerald Holton wrote in their book, What Happened to the Children Who Fled Nazi Persecution, “escaped the fate of 1,500,000 racially or politically targeted children who died in the Holocaust.” The Nobel Prize-winning neuroscientist Eric Kandel, the historians Peter Gay and Fritz Stern, and the chemist Carl Djerassi—who was instrumental in developing the first contraceptive pill—all migrated to the United States and found acceptance and lofty positions here.

But a list of elites hardly tells the larger story. In the late 1990s, when I was the provost of Columbia University, I examined the percentage of the university’s arts-and-sciences faculty who were born abroad. More than 40 percent had come from foreign countries. A quintessential example, not from Columbia, is the Princeton University professor Marta Tienda, who is today one of nation’s most distinguished scholars of sociology. Tienda’s  father, Toribio Tienda, was a Mexican immigrant who risked his life crossing the Rio Grande illegally and worked 16-hour days at two jobs so his daughter could better herself. A superb student, she did just that. Today, if Toribio Tienda were alive, he could be rounded up and sent back to Mexico—and perhaps he might take his daughter with him.

Finally, recent statistics on America’s success at conducting Nobel-quality research suggest that the contribution of immigrants to domestic universities is still very much alive. In 2016, six Americans won prizes in physics, chemistry, and economics. Each of these winners was an immigrant. They became Americans by choice, “bringing their energy and innovation to the nation.” In short, a pipeline of talent was opened for a wide range of American research universities in the 1930s that has never stopped flowing—and those immigrants, some of whom have retained their citizenship in other nations, have contributed mightily to the United States’s supremacy in the world of higher learning.

For more than 75 years, the United States has been the destination for ambitious, talented, and leading young scholars who have wanted to live and work with the best colleagues and students. They have assimilated into an incredibly creative and adaptive set of universities. American-based scholars also collaborate with foreigners, bringing nations closer together. Worldwide, from 1988 to 2009, the proportion of scientific and engineering papers that were coauthored with foreigners rose from 8 percent to 23 percent. Foreigners have thrived in the United States, and the nation has benefitted in innumerable ways from their creativity. They have also benefitted significantly from collaborations with scholars based in other nations. Is this history about to end?

Students from other nations have also been a great source of intellectual energy and diversity at American universities. Relatively recent data published by the National Science Board (2012) document the continued rise in total foreign students in the United States–at both the undergraduate and graduate levels. “About 60 percent of all foreign graduate students in the United States in 2010 were enrolled in S&E [science and engineering] fields, compared with 32 percent at the undergraduate level.”

According to the Institute of International Education, in 2015-16, the largest number of foreign students came from China (about 330,000), India (165,918), and Saudi Arabia (roughly 61,000). There is widely considered to be a paucity of American students who study science and engineering. The foreign students who study in so-called STEM fields—some of whom remain in the United States after graduation—make up for this deficiency in the domestic educational system. China, for example, sends large numbers of graduate students to the U.S. for training and, as I wrote in my book, more than 80 percent remain in America country after they graduate, taking jobs in computer science,mathematics, and engineering. I was recently told by a colleague that at his university, foreign applications this year were down by around 15 percent. Were this source of talent to dry up or disappear, the nation could find itself with a deep deficit of talent to fill highly skilled jobs—to say nothing of the research departments at universities that focus on these subjects.

As one of his first acts in office, President Trump signed Executive Order 13769, “Protecting the Nation From Foreign Terrorist Entry Into the United States.” Washington state and Minnesota challenged this order almost immediately. Because the order was aimed at Muslims from seven countries, the states’ attorneys general claimed it violated the Establishment Clause of the U.S. Constitution and the Equal Protection Clause of the 14th Amendment. After the stay of the order by the U.S. District Court in Seattle, the case was heard by the 9th Circuit Court, which upheld the lower court’s decision. In order to meet the requirement of “standing,” the Circuit Court wrote: “The States argue that the Executive Order causes a concrete and particularized injury to their public universities, which the parties do not dispute are branches of the States under state law.” The intense scrutiny the executive order places on Muslim and others—even scholars from Europe who are being questioned at airports about their purpose for coming the United States—will have multiple negative consequences on the country’s universities.

Universities and colleges have become more international both by choice and necessity. Many of the nation’s great universities actively recruit students from around the world to increase the diversity of the college experience for all of its students. Moreover, at many of the finest public universities, where the states have reduced per-full-time-pupil spending by a median of more than 20 percent, foreign students are superb targets for seats: They often pay full tuition, which helps make up for the states’ budgetary strangulation of their flagship universities. But many of these scholars and students may soon begin to self-select out of a chance to come to the United States. More than 70 years ago, Robert Hutchins, then the president of the University of Chicago, observed that the problem with witch-hunts was “not how many professors have been fired for their beliefs, but how many think they might be.” If the United States becomes less appealing to scholars from abroad, they may well stay home, depriving America of their talent. Fear and uncertainty have become the order of the day. Executive orders or legislation that represses immigrant groups often, historically, morph into laws against American citizens. None of this bodes well for those interested in studying, teaching, or conducting research at American universities.

Beyond the particulars, America was once considered a compassionate and welcoming nation—opening its arms to those yearning to breathe free. The social and economic consequences of the imminent changes in immigration policy only expose the country’s dark side—one that we that, regretfully, could hurt the nation’s economy, pace of discovery, and the social fabric.