Steve Roberts.

They’re coming from … all over the world,” thundered Donald Trump in a recent radio interview. “They’re poisoning the blood of our country.”

Trump got it exactly wrong. Yes, immigrants are “coming from … all over the world” to the U.S., but there are not enough of them. Foreigners don’t endanger the American bloodstream, they enrich it. We should be expanding the number of newcomers we let into the country, not reducing it. And this is not a matter of charity or morality, although morality matters. It is in our own national interest.

As the grandson of immigrants from what are today Poland, Lithuania and Belarus, I am prejudiced on the subject, but the evidence is overwhelmingly clear: “America needs immigrants to solve its labor shortage,” headlines CNN. “Rebound in immigration comes to economy’s aid,” reports The Wall Street Journal.

“There is no question: We need more immigration,” Adam Ozimek, chief economist at the Economic Innovation Group, a nonpartisan business organization, told the Post. “Immigrants aren’t just workers, they are particularly flexible, mobile workers, who help address acute labor shortages wherever they emerge. And that’s particularly important in this constrained economy we’re facing right now.”

“Immigrants in America are nearly twice as likely to start a company as the native-born and four times likelier to win a Nobel science prize,” writes The Economist. “Less-skilled migrants fill gaps in aging labor forces and free up locals for more productive tasks (for example, when a foreign nanny enables two parents to work full-time).”

This is not to minimize the crisis on the Southern border, where even many progressives agree the Biden administration has been slow and sluggish in responding to the current flood of illegal immigrants. “We all know there’s a problem at the border,” admitted Senate Majority Leader Chuck Schumer. “The president does, Democrats do and we’re going to try to solve that problem consistent with our principles.”

But the contentious debate over the border masks a larger long-term issue: how to open America to more legal immigrants. To all those who share Trump’s bloodlust on this issue, please answer these questions: Who is going to cut your lawn? Pick your fruit? Serve your meals? Take your temperature? Care for your parents? Or your children?

Who is going to create the business that revitalizes your hometown? Or start the company that gives you a job? Who is going to invent the device or drug that saves countless lives? Who is going to sing the song or write the book or make the film that entertains you? Who is going to pay the taxes that finance the benefits you need in your old age?

Immigrants, that’s who.

But the system of legal migration, creaky in the best of times, has recently taken two major blows. The pandemic slowed the movement of migrants worldwide, and Trump’s restrictive policies strangled it even further. Instead of opening doors, we’re closing them.

“Despite growing demand to help fill 8.7 million open jobs with skilled and unskilled foreign-born workers, strict quotas keep out millions of qualified immigrants every year,” reports the Post. “Demand was so high this year that the State Department was forced to restrict many types of visas, including — for the first time in years — those for nurses. Getting a coveted pass to enter the United States means waiting in backlogs for years in a neglected bureaucracy of overlapping, resource-starved federal agencies.”

“The legal immigration system is collapsing under its own weight,” says Theresa Cardinal Brown, a former federal immigration official now at the Bipartisan Policy Center.

Congress has been paralyzed on this issue for many years — the last major immigration reform was enacted in 1986 — and demagogues like Trump who inflame the issue for political reasons make the problem even worse. So it’s hard to be optimistic.

Still, there are plenty of workable proposals out there to fix the system. One comes from two Republican governors, Spencer Cox of Utah and Eric Holcomb of Indiana, who wrote in the Post that their states have a combined total of almost 330,00 unfilled jobs at the moment. Pass a law, they argue, that gives states the authority to directly sponsor immigrants who settle within their borders.

“We … need immigrants who are ready to work and help build strong communities,” they wrote. “As it is, the standstill on immigration hobbles both parties and, more seriously, endangers America’s long-term well-being.”

Trump is wrong. They are right. So is the character from the musical “Hamilton” who sings, “Immigrants, we get the job done.”