The United States has a de facto ban on immigration. We can debate about whether this prohibition is necessary, but its existence is undeniable. Other than a few exceptions for family members, refugees, and the highly-educated, it is virtually impossible to come to the United States to live and work legally.

Historically, America held its doors open to all. But in the 1920s, a coalition of unions, progressives, and eugenicists combined to slam them shut. Within a year of passing Alcohol Prohibition, America also banned almost all forms of immigration, cutting immigration by nearly 80 percent.

Alcohol regained its legal status, but immigration never quite recovered.

Today, the government lets in almost a million immigrants each year, but this impressive-sounding number misses the entire legal, historical, and global context of our immigration system. We must compare it to the number who would come if only they could do so legally — and the reality is that most types of immigration are entirely prohibited. To deny the ban on immigration because it has exceptions is like denying Alcohol Prohibition because it allowed communion wine.

The half million people apprehended at the border each year and the 11 million unauthorized immigrants in the country are the clear evidence of this prohibition. The massive immigration underground points to an obvious yet largely ignored fact: If there was a legal way for them to come, they would have taken it. But, trouble is, one doesn’t exist.

The drastic shortage of visas is evident in the unbelievably long wait times for permanent residency. For certain categories, the wait is decades. For employment-based visas, certain Indian and Chinese workers will wait more than a decade. For Mexico, three different family-based categories have wait times over 18 years. There’s northward of 4.3 million people in these lines alone.

Yet these impossible lines hide a deeper problem: most would-be immigrants have no line to stand in at all.

The reality is this: 92 percent of legal immigrants are either 1) immediate family members of US citizens or permanent residents, 2) refugees or asylees, or 3) college graduates — and over 80 percent those needed an advanced degree or at least $500,000 to invest in projects in the United States.

This leaves less than 65,000 visas for everyone else. More two-thirds of these come through a lottery system for which 11 million people applied last year. People in most of the largest countries in the world, including India, China, and Mexico, aren’t even eligible to apply.

This legal flow amounts to barely 7 percent of the average number of immigrants apprehended at the border each year since 2004 (and, of course, that doesn’t count those who crossed successfully, or those who entered and overstayed their visas, or those who would come if there was a legal opportunity). For people without a college degree or a close American relative, the Statue of Liberty’s “Golden Door” is almost completely shut.

Meanwhile, PhDs, scientists, movie stars, pro-athletes, and other elites have a number of different work visas available to them. These allow them to live and work year-round in the United States.

By contrast, there is no work visa that allows lesser-skilled laborers to live and work year-round in this country. Unsurprisingly, this lesser-skilled demographic is disproportionately represented in the illegal population, 85 percent of whom lack a college degree.

Another reason we know that illegal immigration is being driven by the lack of a legal alternative is because of what happened when the government allowed foreign workers to come and go legally.

Thanks to a fluke of history, America had a brief period when it experimented with freer migration between the United States and Mexico. In the 1950s and ‘60s, the Bracero guest worker program let in about 5 million Mexican farmworkers. From 1956 to 1965, when the program was at its height, the number of unauthorized immigrants at the border averaged just 41,000, compared to over 436,000 a year in the prior decade.

After it was terminated in 1966 by another union-led coalition, illegal immigration never again fell to such low levels — not even for a single year, let alone an entire decade. By the 1980s, a million or more immigrants were routinely being caught by Border Patrol every year.

Supporters of the ban on immigration will say that America is at its breaking point, that we’re overwhelmed, that we can’t “handle” any more immigrants. But this fear is groundless: As a share of its population, America admitted four times as many immigrants each year in the early 1900s as it did in 2014. For a century from 1830-1929, immigration was twice as high as a share of the population as it was in the last two decades.

In absolute terms, America admits more immigrants than any other country, but relative to its size, US immigration levels are far lower than many Western countries. Controlling for population, Canada, Australia, and New Zealand all have higher levels of immigration than America today — even as high as the United States in the early 20^th century — and they have not collapsed into chaos or poverty.

Immigration prohibition is real. Millions of people cross the border illegally (and thousands of businesses hire them illegally) for the same reason bootleggers had to brew booze in bathtubs. And, for the same reasons we repealed Alcohol Prohibition, we should also finally end America’s ban on immigration.

David Bier is an immigration policy analyst at the Niskanen Center. He is an expert on visa reform, border security, and interior enforcement. From 2013 to 2015, he drafted immigration legislation as senior policy advisor for Congressman Raúl Labrador, a member of the House Judiciary Committee’s Subcommittee on Immigration and Border Security. Previously, Mr. Bier was an immigration policy analyst at the Competitive Enterprise Institute.  

This article was published by The Foundation for Economic Education and may be freely distributed, subject to a Creative Commons Attribution 4.0 International License, which requires that credit be given to the author.