It provides the money for the governments daily operations (at least till the baby boomer start retiring en masse), It is the justification for the numbering and tracking of all Americans, It allows the intrusion into the daily economic (and personal) life of all Americans. This is the basis for our way of life (covert control vs overt control), as it makes all the government controls look like they are voluntary for citizens and keeps them hidden. Doing away with FICA is unthinkable (to Republicans and Democrats) for these reasons.