Last month, the United States made an extraordinary achievement: For the third time in four years, it won the International Mathematical Olympiad.

This is staggeringly impressive. The Math Olympiad is the hardest and most prestigious math competition for high school students in the world. University professors often cannot solve more than one or two of the six problems on the exam. Since 1978, Math Olympiad gold medalists have made up more than a third of the winners of the Fields Medal, the Nobel Prize equivalent for mathematics.

Yet from the U.S. team, James Lin from Phillips Exeter Academy received one of two perfect scores at the competition. (The other went to Britain’s Agnijo Banerjee.) Also from the U.S. team, Andrew Gu, Vincent Huang, Michael Ren and Mihir Anand Singhal all won gold medals, and Adam Ardeishar received a silver medal.

The team, led by mathematics professor Po-Shen Loh of Carnegie Mellon University, is about as American as you can get. After all, its members celebrated their victory by going to McDonald’s. But in this time of charged debates about immigration, it is worth noting that many of the team members are second- or third-generation immigrants. Loh, in fact, is the son of immigrant parents from Singapore. The team’s deputy leader, Sasha Rudenko, is the son of Ukrainian immigrants.

Immigration is often thought of as a way to fill jobs that locals find too taxing, too challenging or too low-status. We typically think of immigrants as working as manual laborers in construction, plumbing, hospitality and agriculture.

But this is not the whole story. Immigrants are high achievers in some of the most challenging vocations, such as mathematics, physics and computer science — all necessary for a technologically reliant society. Each of these fields requires immense dedication and hard work. Mathematics is perhaps the most mentally taxing of these disciplines.

By welcoming and giving opportunities to the Lins, Singhs, Steins, Huangs, Hossains, McArthurs, Onahs, Garcias and Rudenkos of the world — who are eager to learn the difficult math, solve the difficult physics problems and write the difficult code — America renews itself and makes itself “great again,” to borrow language from President Trump. Because of this, America has an Apple, a Google and thousands of smaller cogs that make the U.S. economy the most dynamic in the world.

Every country envies America’s talent pool, yet very few are bold enough to copy the U.S. model of immigration that can recharge stagnant sectors of society. That is why no other country will ever be able to emulate the dynamism of America, whether they are as big as a China or as disciplined as a Germany. The United States’ repeat Math Olympiad wins reflect this truth. If China, Russia and other countries that have devoted tremendous resources to winning the competition cannot beat the United States’ diverse pool of high school students, how can they beat well-funded U.S. companies at innovation?

But if the United States turns its back on the immigrants who have made it “great,” then America in the future will not have the Po-Shen Lohs or Sasha Rudenkos to create the next generation of best-in-the-world innovators and scientists. America will be like every other country — not exceptional and not able to lead the world in every field.

For example, Loh travels to countries ranging from China to Bangladesh to Brazil to teach mathematics to young people. The goodwill he generates is priceless. In my own small way, I try to do something similar: I coach the Bangladesh Math Olympiad team, which won its first gold medal this year — a great achievement that generated unbelievable excitement for the young, developing country. 

I feel privileged to be a part of this, because as a son of immigrant Bangladeshis who grew up in the United States receiving the best that America has to offer, I know firsthand the good that America does in the world. By helping Bangladesh’s students reach greatness, I am taking part in the chain of transformation that liberal and open U.S. immigration policies offer. This culture of aspiration and generosity is America at its best.