Saul Arellano is the seven-year-old son of Elvira Arellano, who's currently holed up in a hole-in-the-wall Chicago church in defiance of a court order to appear to be deported. Saul was recently taken to Mexico and appeared before their Chamber of Deputies (House) asking them to lend their support to his effort.
To the surprise of none, they complied and have passed a resolution asking the U.S. Congress to avoid deporting not only Elvira Arellano, but all other illegal aliens who have U.S. citizen children:
...If the U.S. agrees, it would "create a precedent that will benefit more than 4.9 million children who have been born in the United States and whose parents live under the threat of deportation," said Mexican congressman Jose Jacques, who lived in the United States for 33 years and has an American daughter and granddaughter...
...[Vicente Fox's] spokesman Ruben Aguilar acknowledges that Arellano broke U.S. law, but "we think there exist certain elements of a humanitarian nature that should be taken into account to avoid splitting up the family."
Needless to say, this illustrates the problems not only with illegal immigration, but with guest worker schemes as well: those guests would have U.S. citizen children, and the same techniques would be used to keep "guests" from having to go home.
Contrary to what the linked article by Julie Watson of the AP implies, it's not just "conservative columnists and anti-illegal immigration activists" who think Arellano should be deported, but both major Chicago newspapers. They realize how much damage this case could do to their support for illegal immigration. I'd say we rub as much salt as possible into their wounds by continually discussing that this case illustrates how much we need to enforce our immigration laws and avoid (at the least) long-term "guest" worker schemes.