Re the 75-year shortfall, I simulated an Obama-like plan using the Policy Simulation Group's GEMINI model, assuming a top end to the donut hole of $250k, a 10-year phase in, and benefits paid on the new contributions. This reduced the 75-year deficit by around 36%. However, Sen. Obama has also proposed exempting seniors earning under $50k from income taxes, which would affect Social Security because it receives income taxed levied on retirement benefits; I believe this would increase the deficit by around 10%. Sen. Obama has also proposed exempting low earners from payroll taxes, although the cost isn't yet clear. But overall I would guess that his full plan would reduce the 75-year deficit by around 25%.