You probably don't know his name. And you probably won't see any news of his passing outside of the obit section. But Bob Ball, who died last night at the age of 93, probably played a greater role in expanding and defending Social Security than anyone in the second half of the 20th century.

Ball became a Field Assistant in the Social Security Board's New Jersey field office in 1939. He became Assistant Director of the Bureau of Old Age and Survivors Insurance in 1949. Later he became Deputy Director and then Acting Director. In 1962, President Kennedy appointed Ball a Commissioner of Social Security, where he remained until 1973.

Probably most significant was Ball's advocacy of Social Security and social insurance more generally after his retirement. He was a key member of the Greenspan Commission which made the program solvent well into the middle of the 21st century. And he was around as a key behind the scenes player as recently as President Bush's failed 2005 effort to phase out Social Security and replace it with a system of private accounts.