http://www.thesocialcontract.com/artman2/publish/tsc_17_4/tsc_17_4_walsh.shtml
If you don't want to read the entire thing, in which he lays out his reasoning, scroll down about half-way.
And probably half of Mexico is being claimed as dependents by Illegals working in the US who fill out Tax Returns. Someone I know who employs illegals told me that one of the employees wanted to claim two children in their 20's living and working in Mexico as dependents. Their lawyer told them they could do that. Our government is about as corrupt as they come. There are reasons they are trillions in debt.