President Donald Trump claims “our country is full.” It’s a premise that appears to support the administration’s hostility toward asylum seekers, its rejection of refugees, and its efforts to limit legal migration.

By any objective measure, the president is mistaken. There are about 45 million foreign-born people in the United States, including about 11 million who are undocumented. Each year the U.S. grants permanent resident status to about a million, yet America continues to need immigrants for it to grow and prosper.

If Trump paid attention when he visited Houston Wednesday, he might have looked around our city and seen the strength that comes with immigration.

This is one of the most diverse areas in the country, a place where more than 140 languages are spoken and about 1 in 4 of us are foreign-born. Most immigrants here come from Latin America, but many others are from Asia. They are part of our city’s vibrancy, a cultural and culinary richness for which we are increasingly, and justly, famous. If immigrants are a threat to our nation and a danger to native-born Americans, how do you explain Houston?

Our city is thriving — we’re the fourth largest in the U.S. and growing fast — and migrants help drive the economy, providing labor from a wide range of skills; from the doctor at the medical center to the carpenter at the construction site.

Even the city’s resilience and strength in the face of adversity arebuttressed by our diverse population, said Joel Kotkin of the Houston-based Center for Opportunity Urbanism.

“After Harvey a lot of people were saying, ‘Oh, Houston’s dead,’ but it’s better than ever,” he said. “A lot of that energy comes from migrants and immigrants. Countries and cities that attract new people are the ones that do well.”

The United States is lucky to remain the world’stop destination for immigrants. Without those “new people” the economy would suffer. The nation’s birth rate is at a 30-year low and not enough babies are being born to replace the population. America, without immigration, is inviting a labor crisis over the next decade.

Even more newcomers are going to be needed if we want to keep the “Texas miracle” alive.

Texas’ population is growing about twice as fast as the nation as a whole, with immigration a key reason why, said Pia Orrenius, senior economist at the Federal Reserve Bank of Dallas.

That so many residents of other states have moved here has helped a lot, too, but Pia said it’s been immigration that played the largest role. “There’s no way we can sustain this growth premium without it,” she said. “About 40 percent of growth between 2000 and 2017 has been international immigration.”

Despite immigration’s role in helping states such as Texas thrive, Trump’s anti-immigration rhetoric has found a wide audience. This is hard to explain until we consider the pace of cultural and other change in America over the past decade or two.

Polling after the election found that the strongest support for Trump came from voters who said immigration was the most important issue facing the country. But 66 percent of Trump voters also agreed that the 2016 contest represented the “last chance to stop America’s decline.”

For many Trump voters , including many white evangelicals, the country was changing much too quickly, leaving them desperate to turn back time, said Robert P. Jones, CEO of the Public Religion Research Institute.in Washington, D.C.

“You can see this with support for same-sex marriage, another controversial topic,” Jones said. “In 2008 it was 40 percent; by 2016, it’s only 4 in 10 oppose. A complete flip. If you are a white conservative evangelical Christian, that is a head-spinning amount of change in a short period of time.”

Trump understood that to stand out in the primary he could exploit and even deepen that sense of alienation. He zeroed in on immigration and it worked beautifully. By doubling down in the general election, he squeaked out a victory.

Once he was president, Trump could have taken a different approach — something he’s flirted with from time to time, as when he claimed to “love” dreamers and to want “'the largest numbers ever” of legal immigrants. But his actions have repeatedly belied his words.

Now, with asylum-seekers pooling at the border, he’s again playing up our divisions and acting as though following our nation’s asylum laws is somehow at odds with enforcing our border laws. As Trump slipped in and out of Houston this week, he seemed utterly determined to miss the obvious truth of this city: Immigration is rocket fuel for Houston’s growth and it could be fuel for the rest of the nation, too.