Please forward suggestions for additions to this list to SocSec Defender, but by nature it can't do justice to everyone doing hard work on this every day. Also I have included a number of policy organizations that supply valuable technical and numeric support under Social Security Resources (above):
NCPSSM: National Committee to Protect and Strengthen Social Security and Medicare
Campaign for America's Future: Social Security page, a project of the Institute for America's Future
Social Security Works/Strengthen Social Security
Many more to be added in the days ahead.