FAR FROM the madding crowds and MAGA caps, Mick Mulvaney, the acting White House chief of staff, discovered his inner candor. Appearing at the Oxford Union during a trip to England a few days ago, Mr. Mulvaney let slip that the United States needs more immigrants, lest severe labor shortages and anemic birth rates sap economic growth.

“We are desperate, desperate for more people,” said Mr. Mulvaney, evidently emboldened by the 3,600 miles separating his speaking venue, where TV cameras were not in evidence, from the White House. “We are running out of people to fuel the economic growth.”

That’s hardly a jaw-dropping prescription for an economy that for 22 straight months has featured more available jobs than unemployed job-seekers. It’s in line with the views of most economists and employers in an array of worker-hungry industries, not to mention Republican orthodoxy until Donald Trump, having weaponized nativism, devoured the GOP.

More startling was the distance between Mr. Mulvaney’s analysis and his boss’s anti-immigration policies and rhetoric. Both have intensified in this campaign season. Mr. Trump talked about bloodthirsty “criminal aliens” in his State of the Union speech as his administration slammed shut the doors: slashing refugee admissions to their lowest level in decades; adding countries to the travel ban list; barring most asylum-seekers; disqualifying immigrants likely to need public assistance; tweaking the rules to deny visas to victims of crime and human trafficking; and more.

America is “full,” Mr. Trump declared last spring, preposterously. In fact, unemployment is at historic lows, and the native-born labor force is shrinking as about 300,000 baby boomers reach retirement age each month. Employers have raised the alarm about acute shortages of skilled and unskilled labor up and down the wage scale — construction workers; maintenance and repair workers; truckers; firefighters; furniture-makers; nurses; home health aides; farm workers.

The tight labor market is pushing up wages for some workers and has provided opportunities to teenagers, students, ex-convicts, long-term unemployed, the disabled and others for whom the barriers to employment once looked daunting. Close to 160 million Americans are employed, a near-record.

Those are good things. But when dozens of industries warn that worker shortages are constraining growth and investment, it’s worth listening — and reckoning with the demographic reality that the numbers of native-born Americans are inadequate to fuel even moderate growth. It makes sense to recalibrate immigration policy to meet the labor market’s future demands, including by admitting more high-skilled workers. It’s self-defeating to use immigration as a political whipping boy, which will only put Mr. Mulvaney’s self-evident prescription further out of reach.

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