In doing so they betray their most stalwart voters: black Americans. How? Illegal migrants compete directly with black Americans for jobs, causing unemployment and decreasing wages.

Official estimates suggest that over 1 million people will illegally migrate into America in 2019. The Democrats welcome them with open arms -- they have even offered to give them "free" healthcare.

Before discussing the economic impact of illegal immigration, how many aliens live in America?

At the Hot Gates

Pew Research suggests that some 11.1 million illegals reside within our borders. Although this falls in line with figures from the Department of Homeland Security, many believe the true figure is much higher. Why? Two reasons.

First, the "official" figures do not include the children of illegal immigrants who were born in America -- so called "anchor babies." Although they are natural-born citizens, these individuals are only here because of their parent's criminal activity.

Can Americans blame anchor babies for their parent's actions? No. But there is no denying that the addition of 6.5 million additional children is a burden on America's welfare state -- especially since their parents contributed nothing towards its creation, and little towards its maintenance.

Second, the official aggregate figures suspiciously plateau in 2007. The explanation is that after 2008 the number of migrants fell and deportations rose to an equilibrium point. However, there is little evidence that migration rates fell, and the reason deportations increased is because the Obama administration simply changed the definition of "deportation" to inflate the numbers.

If the official figures are flawed, then just how many illegal aliens reside in America?

A relatively recent study conducted by Dr. Mohammad Fazel Zarandi of the Yale School of Management estimates that some 22.8 million illegal immigrants live in America. This figure draws upon more recent data and a variety of (often-ignored) sources. It is probably the most accurate estimate.

Regardless which estimate is used, the impact of illegal immigration is magnified because alien populations are heavily concentrated in a number of specific states and cities. For example, California alone is home to nearly one-in-four illegal migrants, and the majority of these live in the Greater Los Angeles area. Meanwhile, cities like St. Louis and states like North Dakota have very few illegal aliens.

These millions of illegal workers distort America's labor market, and disproportionately harm black Americans.

Into the Octagon

In 2008 Vernon Briggs, Emeritus Professor of Labor Economics at Cornell University, testified before the U.S. Commission on Civil Rights. He stated matter-of-factly that there was "little doubt" that black Americans are the "major loser" in the immigration equation. Briggs explains: "Because most illegal immigrants overwhelmingly seek work in the low skilled labor market and because the black American labor force is so disproportionately concentrated in this same low wage sector, there is little doubt that there is significant overlap in competition for jobs" between aliens and black Americans.

Basically, illegal migrants generally work low-wage jobs -- the very jobs black Americans tend to work. Likewise, both aliens and blacks tend to reside in major cities. Taken together, this means that migrants and black Americans compete directly for the same jobs, which reduces wages and employment opportunities.

Unfortunately, black Americans fare worse in this head-to-head struggle because illegal aliens often work under-the-table for less than minimum wage and forgo expensive employer-provided healthcare plans. They undercut the labor-market's mandated floor and pull the rug out from under American workers.

These findings are backed up by decades of studies. For example, a 1995 study conducted by Augustine Kposowa found that when compared to white Americans, "non-whites appear to lose jobs to immigrants and their earnings are more depressed by immigrants." These non-whites mostly include black and Hispanic Americans.

Likewise, a 1998 study of the New York area by David Howell and Elizabeth Mueller of the New School for Social Research found that a 10 percent increase in the immigrant share of any given occupation reduced wages of the black men working in that occupation by five percentage points. Furthermore, the relationship held across a wide range of jobs. Basically, more immigration meant lower wages for black Americans.

I have cited these older papers not because nothing newer exists -- the work of Harvard University's George Borjas is a good starting place -- but to show that economists have known about this for decades. And yet, the Democrats have done nothing to save their most loyal voters from the ravages of illegal migration.