According to the Social Security Administration, "at its inception, the SSN's only purpose was to uniquely identify U.S. workers... That is still the primary purpose for the SSN." That is, the SSN is a (semi-)unique identifier, not a secret password.
In 2014, CNN reported that hackers illegally obtained more than 6.5 million SSNs. By assuming that only the account holder knows their SSN, many businesses open the door to identity theft.
Best practices for authentication require multiple factors to prove that you are who you say you are. We ask that the President introduce legislation to make it illegal for businesses or governments to use the SSN as a single factor for authentication. To prevent identity theft, multi-factor authentication should be mandated by law.