Randy Alcorn, Senior Writing Fellow for Californians for Population Stabilization (CAPS), in the Sep. 2007 CAPS online article "A Presumption That Taxes Probability," wrote:

“While it is empirically true that illegal immigrants are hard working, the presumption that they pay their fair share of taxes is not as visibly verifiable or probable…

Although illegal immigrants pay billions of dollars in Social Security taxes, Social Security taxes are not the main source of revenue for state and federal government—income taxes are…[W]hile illegal immigrant workers have less opportunity to avoid Social Security tax withholdings, they do have opportunity and motivation to avoid income tax withholdings.

So, even if an illegal immigrant worker, who in order to reduce tax withholdings had claimed exemptions for dependents living in Mexico, decided to file tax returns, he or she would likely have a larger tax liability than expected. What are the odds that he or she would come up with the money to pay the additional tax bill after the IRS denied the non-qualifying exemptions? And, if the illegal alien falsely claimed that the dependents did live in the U.S., he or she would still be evading his or her fair share of taxes…

By evading taxes, benefiting from taxpayer provided services, and undermining the wage scale of legal workers, it is highly unlikely that illegal immigrants are a net benefit to most Americans.”

Sep. 2007