This past week, the European Union refused to open its borders to American travelers because it does not deem the United States “safe” as a result of a surge in coronavirus cases here. Arizona, a state with 7 million people, has had more cases daily than the entire E.U. So to protect the health of its members, the E.U. will continue to deny entry to U.S. travelers for at least another two weeks.

At the same time, the Trump administration has announced that it will require international students to leave the United States if their course of study is online, despite the ongoing health risks associated with resuming in-person classes amid the coronavirus pandemic. This follows policies that impede the entry of international faculty, physicians and researchers, as well as a spate of policies that have all but ended the right to seek asylum in the United States.

The result? The United States is isolated from the world because of the Trump administration’s failure to stop the spread of the coronavirus and its punitive immigration policies that aim to exclude nearly all foreign-born people.

This isolationist agenda is starkly different from a century ago. As Europe endeavored to rebuild itself from the devastation of World War I, America and Americans provided much needed funds, expertise, ideas and inspiration — and Europeans welcomed them. Moreover, even in a time of rising xenophobia and immigration restriction, the United States made space for foreign-born professors and students, recognizing their role in fostering a rich academic life at home, as well as furthering the mission and image of the United States in the world.

The life of Rabbi Israel Friedlander (1876-1920) shows just how essential foreign-born professors were to enriching life in the United States and abroad. Polish-born and German-educated Friedlander was drawn to New York at the turn of the century by the offer of a professorship. He was attracted to the vitality of Jewish intellectual life and the exchange of ideas he saw there. He also admired Americans’ civic activism, and after volunteering for the American Red Cross in the Middle East, he traveled throughout Eastern Europe, distributing American dollars, flour and medical aid to those in need on behalf of the American Jewish Joint Distribution Committee.

Friedlander arrived in Poland for his mission at a time when U.S. dollars, American scientific knowledge and values had launched America into what publisher Henry Luce would call the “American Century,” a century in which U.S. influence dominated on the world stage. President Woodrow Wilson led the effort to eschew isolationism from Europe and embraced international cooperation between the various European powers. Although Wilson harbored white-supremacist and racist views, his call for “national self-determination” was taken up by colonized people around the world. The ideals and templates offered by America were embraced by people in places such as China, Egypt and Poland as groups searched for new models through which to engage the world.

American influence was spread not only through direct governmental interactions following Wilson’s agenda, but also through the dramatic growth of American nongovernmental organizations (NGOs), which operated alongside formal state bodies. World War I created an unprecedented welfare crisis in Eastern Europe, with millions dead, homeless, unemployed and starving. With national borders in flux, civil war raging, a flu spreading and Jewish communal resources totally depleted, Jews in this war-ravaged region turned to compatriots in the United States for help. American Jewry responded enthusiastically to their calls, raising millions that were sent to Eastern Europe between 1919 and 1939 through organizations such as the American Jewish Joint Distribution Committee to help rebuild the communal health-care, education and financial systems there.

Friedlander, like dozens of American volunteers, used the strength of the U.S. dollar against the Polish mark to amplify American Jewish support for Jews in the region. He understood the power of microfinance and went from small Jewish community to community in Eastern Europe to dole out funds and see what was needed. He was murdered as he traveled between two small towns in Ukraine.

After he was killed, by Bolshevik forces in a robbery gone awry, the American Jewish philanthropic organization he worked for did not recoil, but persisted in rebuilding the region. Distributing over $35 million in aid in Eastern Europe over the next two decades, the organization reflected American Jews’ understanding of the increasingly important role America would play in the world. This organization would send dozens more shipments of American flour to Poland to feed the hungry, build soup kitchens, provide health care (building the first modern nursing school in Warsaw in 1922), provide models for democratic governance and offer loans to those wishing to start businesses to rebuild their lives after the war. It embodied a view of international connection and cooperation, which was rejected by Congress as the United States opted not to join the League of Nations and countries like Italy and Germany veered toward fascism.

But Friedlander’s legacy — and that of the United States emerging in the aftermath of WWI as a voice for international cooperation and peace — is something we should all consider today as the administration seeks to eviscerate the unique environment for the exchange of ideas nurtured in this country’s university system.

And yet, far from working with other parts of the world that are managing the crisis more effectively, the Trump administration is isolating Americans more and more, from the world and from one another. Cutting off global connections does not empower the United States or its citizens, but weakens it to the core, exposing it to greater risk.