Social Security Number "No-Match" , I-9 and Homeland Security: Someone Explain This One

The Department of Justice filed an appeal, on behalf of the Department of Homeland Security, on the injunction issued by a San Francisco federal judge on the implementation of the "No-Match" Rule. Michael Chertoff, Secretary of the Department of Homeland Security issued a statement on December 5th regarding the No-Match Rule stating that " I believe that the No-Match Rule is a major step forward in preventing employment of illegal migrants. Contrary to the ACLU’s incorrect statements, the rule is not harmful to legal workers. DHS is not abandoning it."

He further stated: "Employers receive a No-Match letter from the Social Security Administration when an employee’s name does not match the social security number it has on file. Sometimes there is an innocent explanation for this discrepancy, such as a clerical error. But sometimes the discrepancy reflects the fact that the employee in question is an illegal alien. When employers receive such No-Match letters, they are on notice that the employees in question may not be authorized to work."

He goes on further to state how important the No-Match letters on Social Security Numbers is to the security of The United States. I happen to agree with him but PLEASE, SOMEONE EXPLAIN TO ME, if this is so important why is it that THE SOCIAL SECURITY NUMBER ON THE NEW I-9 IS VOLUNTARY! Go figure.