Carly Goodman is a historian of immigration and American foreign relations. She is a Mellon/ACLS Public Fellow and communications analyst at the American Friends Service Committee.

A woman holds up a sign outside the Capitol in support of the Deferred Action for Childhood Arrivals (DACA) program on Dec. 5 in Washington. (Jacquelyn Martin/AP)

Last week, President Trump launched his most recent assault on immigrant communities. The new target: families. He renewed his call to end two of the pillars of legal immigration: a program that allows U.S. citizens and permanent residents to bring their immediate families and close relatives to join them, and the diversity visa lottery.

Not only is Trump wildly mischaracterizing how these programs work, but he is also using this distortion to advance dangerous, racist ideas about immigration.

Over the past 50 years, our immigration admissions system has served key values to which our country aspires. Central to this policy has been embracing family, welcoming diversity and recognizing the humanity of all people no matter where they were born.

It was not always this way. In 1965, American reformers and policymakers took dramatic steps to integrate these values into immigration policy, ultimately making family, not nativism, the bedrock of U.S. immigration.

That year, Congress passed the Immigration and Nationality Act, also known as the Hart-Celler Act. It was a significant policy reversal, aimed at combating the values of racism and nativism that had dominated immigration policy since the 1920s. Prior to Hart-Celler, the United States had favored immigration from Northern and Western Europe, while discriminating against Southern and Eastern Europeans, and largely excluding people from Asia and Africa through a system of quotas. The national origins system then in place allotted immigrant visas based on a person’s country of origin, and just three countries — Great Britain, Germany and Ireland — accounted for three-quarters of immigrants through the middle decades of the 20th century.

But World War II and its aftermath opened new debates about how racism harmed American society. African American civil rights activists took advantage of these new conversations about the dangers of white supremacy to call for meaningful policy reforms, including desegregating schools, banning racial discrimination in employment and protecting voting rights.

The Cold War also created space to address discrimination in the United States because the whole world was watching and could see the disconnect between stated American ideals and the stark reality of systemic racial inequality.

In this context, policymakers felt an urgent need to address an immigration system that excluded people from all over the world on the basis of race and national origin. Such a discriminatory policy undermined the international message of freedom and equality the United States claimed came with democracy.

So when Congress passed the act in 1965, it removed the racist quota system and removed references to race in immigration law. As President Lyndon B. Johnson signed the bill into law, standing in the shadow of the Statue of Liberty, he remarked that the act repaired “a very deep and painful flaw in the fabric of American justice,” correcting a “cruel and enduring wrong in the conduct of the American nation.”

In its place, the act created a three-pronged immigration admissions system that was largely based on family unification, as well as skills and refugee admissions. Recognizing the “harsh injustice” of the racist national origins quota system, Johnson argued that the new immigration system, with its strong emphasis on the centrality of family, would make Americans “truer to ourselves both as a country and as a people.”

Both liberals and conservatives agreed that family unity should be the central tenet of immigration admissions. Some policymakers focused on the hardship faced by people who could not reunite with their foreign-born relatives and the moral imperative to keep families together. Others embraced family reunion in order to preserve the status quo. Because immigration had been so strongly skewed toward white Europeans in the past, by making family relationships the basis of immigration admissions, these legislators believed that the new system would continue to favor white Europeans.

Family unity was a strong shared value that transcended partisan and ideological divides, despite its different interpretations and meanings to different people. And with a few tweaks over the years, the family immigration framework created in 1965 remains at the core of U.S. immigration admissions today.

In 2015, for example, of the 1 million new green-card holders, nearly two-thirds were immediate relatives or close family members of citizens and permanent residents. Fourteen percent entered thanks to employment preference, while another 14 percent were adjusted from refugee or asylum status, and just 5 percent were diversity lottery winners (a fourth category of immigration that was created as part of the Immigration Act of 1990).

But contrary to conservative reformers’ expectations, the family preference system did not continue the status quo of privileging white, European immigrants. Instead, it created new opportunities for immigrants from Asia, Latin America and Africa to move to the United States to join their immediate families and to bring other close family members to join them. This has reshaped generations of immigrants and substantially changed the demographics of the country.

How the United States responds to these changes will be a test of what values it aspires to.

Although polls show that strong majorities of Americans today believe that immigration is a good thing for the country, a nativist backlash has also emerged, with white nationalists, immigration restrictionists and members of the Trump administration seeking to dramatically curtail immigration to the United States. That is what we are seeing in the president’s call to end family migration, or as he has put it “chain migration,” referring in a pejorative way to the networks of families that have immigrated, over time, to the United States.

But chains do not migrate — people do. Families do.

Reuniting families through the immigration system is not only humane — recognizing that for many people, families are a source of love and support — but also contributes to stability, prosperity and stronger communities: Having support networks increases the odds of people succeeding and contributing to their communities. Some experts believe that this focus on family unity is one reason the United States has been able to attract talented immigrants, and that family-based immigration encourages dynamism, learning and flexibility.

Many families are threatened by Trump administration policies. Ending DACA (Deferred Action for Childhood Arrivals) and terminating Temporary Protected Status has put thousands of long-term residents of our communities at risk of deportation, often forcing parents to leave their children or aging parents without caregivers. Raids by Immigration and Customs Enforcement have put people in detention and deportation proceedings, threatening and terrorizing families that are deeply rooted in our communities.

At the same time, the Trump administration is calling for an end to the diversity visa program, which is designed to attract people who dream of making the United States home but who do not have family members to sponsor them. This program has substantially diversified immigration since the 1990s, and the United States benefits from it in many ways, earning goodwill abroad and inspiring people around the world. Not recognizing diversity as valuable, Trump wants to shut it down.

While everyone can agree that improvements in the immigration system would be desirable, the Trump administration’s calls to close the gates to family immigrants and end the diversity visa lottery, not to mention reduce the resettlement of refugees, are at disturbing odds with the ideals that we claim to aspire to. Instead, these efforts echo the “cruel and enduring wrong” that Johnson decried as he signed the Immigration and Nationality Act into law.

The Trump administration and extreme anti-immigrant groups are launching a coordinated attack on immigrants, seeking to discredit and dehumanize people at the heart of our communities. Attacks on so-called “chain migration” are designed to foster nativism and xenophobia, and have nothing to do with security. What makes people less safe is when we lack strong communities, when we fail to take care of one another and when people are made to live in fear. That is exactly what Trump’s attacks on immigrant families will accomplish. Are these the values we should aspire to in our immigration policies?