NASHVILLE, TN (By Charles M. North and Bob Smietana, Tennessean) June 21, 2008 ― Inez and Antonio Valenzuela sell tacos. According to Business Week, the young couple started with only a small sidewalk stand. Five years later, they were operating out of a $70,000 trailer pulled by an $11,000 used van.

They're open eight hours a day, six days a week. They earn more than the U.S.-average-household income. They have checking and savings accounts. They pay income taxes. They dream of someday expanding their business by buying additional trailers.

The United States is a land of immigrants. Waves of immigrants arrived from various parts of Europe during the open-borders era of the 19th and early 20th centuries. In 1924, though, Congress severely limited the number of immigrants allowed into the United States. Clear favoritism was shown to people from northern European countries. In 1965, Congress changed the law again. America's borders reopened to immigrants from all over the world, though quotas were set on the sending countries and priority went to people with family already in the United States.

The upshot of these legal changes has been that immigrants today are very different from their predecessors.

In the 1970 census, 63 percent of immigrants (most of whom were admitted under the 1924 law) were born in Europe or Canada. In 2000, when most immigrants had been admitted under the 1965 law, only 14 percent of them were born in Europe, while 48 percent were born in Mexico, Central America and the Caribbean, and 27 percent were born in Asia.

Today, 30 percent of immigrants are in America undocumented, according to a study by the Pew Hispanic Forum.

What you call immigrants without legal permission to be in the United States can be rhetorically loaded. Advocates of more open immigration have called them "undocumented workers." Jeffrey Passel's report for the Pew Hispanic Center referred to them as "unauthorized migrants." Critics have called them "undocumented aliens" or worse. We will call them "undocumented immigrants." All we intend from this label is that they are immigrants, and that they do not have legal permission to be in the United States. That label does not imply that there is anything "undocumented" about them as human beings.

Perceptions are wrong

The highest-profile immigration-related issue today centers on undocumented immigrants. Unfortunately, the debate is littered with wrong perceptions. As New York Times reporter Daniel Altman put it, "Undocumented immigrants do not just pick fruit, they do not just work off the books, they rarely earn less than the minimum wage and they may even be raising employment without harming incomes."

It's hard to know how many undocumented immigrants are in the United States. They aren't usually interested in talking to government survey takers, after all. But a good recent estimate came from Passel in a research report for the Pew Hispanic Center. He concluded that there were 11.1 million undocumented immigrants in 2005, split into 5.4 million adult males, 3.9 million adult females, and 1.8 million children. More than 75 percent of these undocumented immigrants were from Mexico and other parts of Latin America. And 7.2 million undocumented immigrants have jobs — about 5 percent of all U.S. workers.

Undocumented immigrants get into the United States in one of two ways. Most "enter without inspection" by crossing a border (usually the Mexican border) without going through an official entry point. But 25 percent to 40 percent enter lawfully on a tourist or other visa and then stay on past the visa's expiration date.

What jobs do undocumented immigrants have? They are most common in jobs such as construction work, farm work, meat processing, grounds maintenance, housekeeping and food service (mainly cooking and cleaning). According to Passel, 94 percent of undocumented male immigrants work, compared with 86 percent of legal male immigrants and 83 percent of native-born men. Female undocumented immigrants are less likely to work than female legal immigrants and native-borns.

Of course, this makes sense. People move for a reason. Latin Americans come mainly for economic opportunity. So more men come to the United States undocumented than women — and when they get here, they work.

Undocumented immigrants are not usually forced to work at substandard wages. Economist Gordon Hanson of the University of California at San Diego reports that average wages for all Mexican immigrants were generally $8 to $12 an hour, depending on age and education. Even though these numbers include earnings of legal immigrants, Hanson said there is not a large difference in pay between legal and undocumented immigrants.

Arguments don't wash

Critics of undocumented immigration are everywhere. One example is Tom DeWeese, president of the American Policy Center. "Our nation is being flooded by people who don't care about our heritage or culture," he wrote on the APC's Web site.

DeWeese thinks that the U.S. government should "stop providing U.S. taxpayer funded programs like hospital care, access to public schools, and welfare handouts. Plans to provide Social Security payments to undocumenteds should never be considered. Stop granting automatic citizenship to babies born to undocumented immigrants (known as 'anchor babies')."

Is DeWeese right about undocumented immigrants? Let's start with the "anchor babies," a pejorative term used to describe children born in the United States to undocumented immigrants. DeWeese seems unhappy that the U.S. Constitution grants citizenship to these children. But his arguments against undocumented immigrants don't hold up.

According to Passel's report, there are 1.8 million children who are undocumented immigrants and an additional 3.1 million children born in the United States to undocumented immigrant parents. Almost half of the adult undocumented immigrants have no children at all in the United States. Among adult undocumented immigrants, men outnumber women three to two. And the 9.3 million adult undocumented immigrants are almost twice the number of their 4.9 million children. These facts don't support the idea that having a child with U.S.-born status is a main driver of undocumented immigration.

In some parts of the country, hospitals and schools are certainly feeling financial strain from serving immigrants, legal and undocumented. Admittedly, school costs are borne mainly by local governments. However, health-care costs are offset by Medicaid and by Medicare's Disproportionate Share program. Undocumented immigrants are not eligible for programs such as TANF, food stamps, WIC and subsidized housing, though a household with at least one citizen can qualify. Even so, these programs do not represent a large proportion of the federal budget.

Plus, since so many undocumented immigrants work, many pay taxes that offset these costs — at least in part. Not just income taxes, either. They pay payroll taxes, sales taxes, property taxes on their homes (or via rent payments), gas taxes and many more.

The Valenzuelas brought a baby with them to the United States and had another while here. But they aren't looking for their U.S.-born child to serve as the family's anchor to America. Their anchor is that successful business they run, the one that allows them to pursue their own mobile version of the American Dream.

No effect on wages, jobs

The real question, though, is this: Do immigrants take jobs away from poor Americans and drive down wages for the rest? Basic supply-and-demand says that adding more workers to a market (an increase in supply) will lead to lower wages for all workers in that market. So if a large number of workers from Mexico seek construction jobs in the U.S., then construction wages will fall, and some American construction workers may end up out of work. If many engineers from India or China come to the United States and seek jobs, then some engineers will be paid less and some American engineers may not find jobs. Of course, this assumes that all other things don't change — most notably, demand for workers.

It turns out that studies can't find any major effects of immigrants on either wages or native-born employment. At worst, the effects are negative but small. Immigrants may "take" a few American jobs and push wages down a little bit. But it's more likely that immigrants flow in because demand for workers is growing. Why? Because the American work force is aging, and because American families are having fewer children.

Fertility in the United States is barely at the replacement rate of just over two children per woman. Plus, about 75 percent of men age 20 and up are already in the labor force; for women, the rate is about 60 percent. The unemployment rate in 2007 is well below 5 percent. When employers want to hire more workers, there aren't enough native-born Americans to choose from. Immigrants come to the United States because American employers need them.

American social-insurance programs need immigrant workers too. Social Security and Medicare mostly benefit the elderly, using taxes on workers. Americans are living longer today, which means that social-insurance costs are increasing. At the same time, post–baby boom generations have been smaller, so that there are fewer workers to support the growing elderly population. Immigrants are new workers who can help solve this imbalance across age groups.

And it's even possible that wages are growing as immigrants arrive. This is because human migration may naturally be accompanied by capital migration. According to Robert LaLonde of the University of Chicago, "Capital is a much more mobile factor than labor is, so if labor's moving in, you better believe that capital's not too far behind."

If he's right, then immigrants are taking jobs that wouldn't exist without them.

Welcome strangers

Bringing in and retaining highly skilled immigrants should be an important part of U.S.-immigration policy. Well-educated immigrants can contribute immediately to producing the high-end goods and services that the United States specializes in. They can help the United States to maintain its global advantage in technology. And they can provide the expanded tax base needed to keep our social-insurance programs afloat.

Attitudes such as Tom DeWeese's are not just troublesome from an economic standpoint, they also run afoul of biblical principles on the treatment of foreigners in our midst. How does denying citizenship to U.S.-born babies of undocumented immigrants (as DeWeese and others would like to do) treat foreigners properly? How does it keep them from feeling like strangers in a strange land?