Army Staff Sgt. Justin Peck, left, and the parents of Otto Warmbier were guests at the State of the Union. (Alex Wong/Getty Images)

The best parts of President Trump's State of the Union speech were all the individuals in the gallery he called out for recognition, from military heroes, to a North Korean defector, to a welder who was said to have benefited from his tax cuts. But, of course, the guest list was carefully curated to support Trump's polemical points, including his animus toward non-Norwegian immigration. Among those cited were two families whose daughters were killed by members of the transnational MS-13 gang, even though immigrants, even illegal immigrants, are much less likely to commit crimes than the native-born.

There are a few missing people I wish the president had invited: the three daughters of Helen Huynh. Who is Helen Huynh? She was an American citizen — one of the people Trump said it was his "sacred duty" to protect — and she died last Friday, in part because of the government's restrictive visa policies.

As The Post has reported, Helen was an immigrant from Vietnam. She came to Southern California in 1991 with her husband, Vien Huynh, who fought in South Vietnam's army alongside American troops. After the fall of Saigon, he spent eight years in a brutal reeducation camp enduring torture. The Huynhs had two daughters before immigrating and another after arrival. The youngest, Tiffany, now in her mid-20s, was born with Down syndrome. Helen was her primary caregiver. Vien did odd jobs such as delivering pizzas and newspapers to support his family.

A year ago, at 61, Helen was diagnosed with acute myeloid leukemia. Her doctors concluded that a stem-cell transplant was the only treatment that could save her life. One of her sisters in Vietnam was found to be a perfect match. All she would have to do is fly to the United States. Except that officials at the U.S. consulate in Hanoi wouldn't grant her a visa. Three times she was rejected.

The consulate was worried that Helen's sister wouldn't return to Vietnam, even though she has a business and a family there. Finally, under pressure from California lawmakers, the visa came through, but the passage of time made it less likely that the transplant — a risky undertaking in any case — would succeed. Helen died a week ago.

This is a tragedy that I feel more keenly than most. My mother is also a refugee from communism, in her case the Soviet Union (where I was born in 1969). She, too, became an American citizen, and she, too, has had a long and productive life in Southern California, in her case teaching generations of college students. And last August, a few months after Helen, she, too, was diagnosed with leukemia. Her doctors hoped that chemotherapy and experimental drug treatments would bring about remission and allow for a lifesaving cell transplant. I was even tested as a potential donor, but I was only a 50 percent match.

In the end, it didn't matter: The chemotherapy didn't succeed, and the transplant couldn't be attempted. While my mom is alive and still feisty at 71, her family and friends are heartbroken that there is no possibility of a cure. But at least we know the doctors did everything they could. How much worse to know that a cure might have been possible were it not for our own government.

The kind of bureaucratic folly that helped to kill Helen Huynh could have occurred in any administration, but it is especially likely under a president who demonizes immigrants and urges tougher standards for admission. The consular officials in Hanoi were just doing as instructed.

Helen's heartbreaking case points to something that Trump never mentions: the high cost of closing our doors to newcomers. Part of the cost is lost prosperity ; immigrants — legal and illegal — work hard and innovate, helping to keep our workforce young and our economy vibrant. Part of the cost is lost security; many immigrants, including noncitizens, serve in our armed forces and provide irreplaceable linguistic and cultural skills for our intelligence and law enforcement agencies.

Part of the cost is harder to quantify: Immigration restrictions prevent families from being reunited in the United States (through what Trump calls, adopting the language of nativism, "chain migration") and rip American families apart. There are all too many people like Jorge Garcia, a landscaper with a wife and two kids who lived in Detroit for 30 years; he was just deported to Mexico because he was brought to the United States illegally as a child. Helen Huynh's death is simply a more calamitous version of the same story — the high price we pay for immigration restrictions.

That is a fundamental point that Trump, in the State of the Union, once again showed he simply doesn't understand. Keeping most immigrants out or kicking them out diminishes our greatness as a nation.

Max Boot, a new Post opinions columnist, is the Jeane J. Kirkpatrick senior fellow for national security studies at the Council on Foreign Relations and the author of "The Road Not Taken: Edward Lansdale and the American Tragedy in Vietnam."