When Donald Trump’s policy adviser Stephen Miller stepped into the White House briefing room Wednesday to defend a plan for reducing levels of legal immigration, Jim Acosta of CNN was aghast and let everyone know it.

Put aside that Acosta believed it was his role to argue one side of a hot-button issue. The exchange illustrated how advocates of high levels of immigration are often the ones who — despite their self-image as the rational bulwark against runaway populism — rely on an ignorant emotionalism to make their case.

At issue is the bill sponsored by Republican Sens. Tom Cotton of Arkansas and David Perdue of Georgia to halve legal immigration. The legislation would scale back so-called chain migration — immigrants bringing relatives, who bring more relatives — and institute a merit-based system for green cards based on ability to speak English, educational attainment and job skills.

Offended by the idea of prioritizing higher-skilled immigrants, Acosta wanted to know how such a policy would be consistent with the Statue of Liberty. When Miller pointed out that Lady Liberty was conceived as a symbol of … liberty, and that the famous Emma Lazarus poem was added later, Acosta accused him of “national park revisionism” — even though Miller was correct.

At the dedication of the statue in 1886, President Grover Cleveland declared that the statue’s “stream of light shall pierce the darkness of ignorance and man’s oppression until Liberty enlightens the world.” He did not mention comprehensive immigration reform.

Lazarus’ poem was added in a plaque in 1903. The words are not, as Acosta and so many others believe, emblazoned on the statue itself — the plaque is now displayed in an exhibition within the pedestal.

All of this might seem pedantic, but the underlying debate is over the legitimacy of reducing levels of immigration and crafting a policy mindful, above anything else, of the national interest. Miller clearly has the best of this argument.

One, making 21st-century policy in accord with late-19th-century poetry makes no sense. We don’t ask, say, whether naval appropriations are in keeping with Henry Wadsworth Longfellow’s “The Building of the Ship” (“Thou, too, sail on, O Ship of State! Sail on, O Union, strong and great!”)

Two, the refugee cap in the Cotton-Perdue bill of 50,000 a year is in the ballpark of recent annual numbers. We actually admitted fewer refugees in the late 1970s and early 2000s, and the Statue of Liberty still stood.

 Three, although Acosta objected to giving a preference to English speakers, knowing English helps people make it in this country, and it’s reasonable to want immigrants to speak the language. As Miller pointed out, this is already a requirement for naturalization.

Fourth, despite the myth, immigration policy has been highly contested throughout American history, and levels have ebbed and flowed. Acosta seems to think that the status quo is the norm, when the past 40 years have represented a historic wave of immigration.

Cotton-Perdue can’t be considered ungenerous in light of how latitudinarian we have been for so long. As the Pew Research Center notes, we have the largest immigrant population in the world. The share of the U.S. population that is foreign-born will soon eclipse the record of 15 percent from around the turn of the 20th century.

The Cotton-Perdue merit system for green cards is hardly know-nothingism. Given how the bill cribs from the system in Canada, it could be described with that cliched banal phrase: “a worthwhile Canadian initiative.”

And an emphasis on skills will take some of the pressure of immigration off the country’s low-skilled workers. Employers may complain about losing access to immigrant labor, but it is simply not true that there are jobs that Americans won’t do. Almost every occupational category in the country has a majority of native-born workers.

If nothing else, Cotton-Perdue will force a debate in an area in which thoughtless sentimentality has long dominated — and if the Miller-Acosta exchange is any indication, will be difficult to dislodge.

Rich Lowry can be reached via e-mail: comments.lowry@nationalreview.com