Patricia E. Dilley (Florida) has published Through the Doughnut Hole: Reimagining the Social Security Contribution and Benefit Base Limit, 62 Adm. L. Rev. 367 (2010). Here is the abstract:

The Obama campaign proposal to address Social Security's future financing shortfalls by increasing the Social Security tax base limit only for those making more than $250,000 per year raises the broader question of the function of the base limit from a Social Security program perspective. The public supports increasing the wage base above all other possible avenues for solving long term financing issues, but the problems with the Obama "doughnut hole" proposal are substantial from several perspectives. In this article, the author suggests that the function of the base limit be reconsidered, and the benefit accrual function of the earnings base be considered separately from the revenue function of the tax base. The little recognized fact that Social Security benefits are based on earnings, not on taxes, should be the central organizing principle in a reconsideration of the base limit and of options for future revenue sources for Social Security.