Among the multiethnic countries of the world, America alone has enjoyed a lasting sense of unity and togetherness. We now run the risk of losing this.

For many, the year 2016 called into question the value of immigration and what it should look like. America elected a man who touted a strictly nationalist agenda, promising to put America first and fix a system that has been neglected for decades. In Britain, officials debated whether to include an “integration oath” for prospective immigrants. In Germany, Chancellor Angela Merkel tried to ban the burqa. And in France, violent protests erupted around the country as citizens demanded a solution to the ongoing refugee crisis.

The debate has not abated. Immigration is still the leading issue in U.S. voters’ minds: 20% of registered voters believe it is the “most important problem facing the U.S. today," according to a new Reuters/Ipsos poll. But as of yet, no real solution has emerged and the rhetoric about immigration, its successes, and its failures, continues to worsen. This debate will continue to divide if we fail to grasp the one thing that guarantees unity and makes multiculturalism work: assimilation.

As he is wont to do, Tucker Carlson started an important conversation in the worst possible way, citing Rep. Ilhan Omar of Minnesota as an example of what happens when migrants take advantage of our broken immigration system.

“The U.S. has done more for other people and received less in return than any nation in history by far,” he said on July 9. "Omar isn't 'disappointed' in America. She's enraged by it. Virtually every public statement she makes accuses America of bigotry and racism. This is an immoral country, she says. She has undisguised contempt for the United States and for its people. That should worry you, and not just because Omar is now a sitting member of Congress. Omar is living proof that that the way we practice immigration has become dangerous to this country."

President Trump furthered this line of thinking in a series of tweets over the weekend, telling Omar and the other “‘Progressive’ Democrat Congresswomen” to “go back and help fix the totally broken and crime infested places from which they came. Then come back and show us how it is done,” he said.

Trump’s comments aren’t just factually incorrect (only Omar was born outside of the U.S.), they’re insensitive and wrong, as are Tucker Carlson’s. They represent a dynamic shift in the way we think about multiculturalism. The diversity Americans once embraced is now used as a weapon against those with which we politically disagree. We are now throwing away the great American achievement of patrimony, the process by which many ethnicities, languages, and religions become one people under one flag. We've been throwing it away for years.

Our immigration system is broken not because it lacks funding or the right number of judges, although those are certainly aggravating factors. Our system is broken because we have neglected the thing that made it work. As Charles Krauthammer once wrote, the genius of American culture has always been its ability to take immigrants and turn them into Americans. But we have failed them, allowing the impractical desire for political correctness to stand in the way of cultural fusion.

The key to assimilation is, of course, language. To know the culture you must first understand it. But in California, voters ended English-only instruction in public schools a few years ago, forcing teachers to teach in the language students preferred, which is typically Spanish. This hurts migrant students more than it helps. There is nothing about Hispanic culture that makes it any more difficult for Central American and Mexican migrants to assimilate. We make it more difficult for them by refusing to immerse these kids in the nation that offers them unparalleled opportunity.

The same is true with Middle Eastern migrants and refugees. I grew up near Dearborn, Michigan, the Arab American capital of the nation. I know from experience (and months of reporting) that the children of these migrants are often more successful than their parents because they are forced to learn English and basic civics in the public education system. In many cases, their success inspires their parents to follow suit and take ESL classes so that they, too, can one day become citizens.

It might not be politically correct, but it is true that successful immigration requires migrants to accept and embrace the values and culture of a nation. It’s only now considered politically incorrect because Americans are moving away from the radical individualism that has given multiculturalism its success, and embracing a tribalist, group rights mentality. The societal engines that lead to success — schools, churches, the arts, etc. — are encouraging a kind of ethnic separateness. Look no further than the public universities, like Stanford University in the 1990s, that are capitulating to cultural radicals and abandoning “Western Civilization” courses because of alleged racial bias.

This cannot last. Assimilation shouldn’t be taboo, it should be celebrated. It has created the greatest ethnic melting pot the world has ever seen. Yes, we should get our immigration system under control. But the U.S. will always have a magnetic attraction because of its inviting economy and culture, and thus, a lasting solution requires permanent policies, like strict standards for the English language and tests on American civics.

The anti-immigrant types will say diversity is a problem. It isn’t. But we do have a responsibility to mold and shape those differences. After all, America is a nation built on this simple truth: Out of many, one.