An important issue associated with empirical research is the extent to which statistical results continue to hold in the post-sample period. Although many tests of robustness within the period of a given study are routinely reported, relatively little attention is paid to model performance in the post-sample period. This paper examines the post-sample performance of the Congleton and Shughart (Econ Inq 28(1): 109–132, 1990) estimates of three public choice models of Social Security benefit levels. The Social Security program is the single largest line item in the federal budget; so, examining the post-sample performance of the Congleton–Shughart estimates also sheds light on the long-run stability of political processes in the United States. In general, we find that the three public choice models perform well in the post-sample period, although there are several caveats to that conclusion. The results of our post-sample study also suggest that the political processes of the United States with respect to major fiscal policies are more stable and robust than news reports suggest.