Congressional Control or Judicial Independence: The Determinants of U.S. Supreme Court Labor-Relations Decisions, 1949-1988

Extending the approach to congressional and regulatory institutions developed by Shepsle and Weingast, this article introduces an ideologically motivated judiciary. The model yields empirically refutable implications which are then tested in the framework of modelling the Court's decisions on industrial labor relations. Using information on politicians' ADA scores, the composition of the Court, and the decisions of the Court, we obtain estimates of (a) the position of the Court in relation to the relevant members of Congress, and (b) the determinants of labor policy through the years. We find, first, that the Court was constrained by Congress over at least half of the period. Second, a 10-point increase in the ADA rating of the relevant member of Congress, or in the imputed ADA rating of the Supreme Court, increases the probability of a pro-union decision by approximately eight percentage points. Third, the imputed political preferences of the Court seem to be well explained simply by its political composition. Fourth, the Court does not seem to defer to the NLRB. Finally, though parsimonious, our model is a relatively good predictor of the Court's decisions, and superior to both a simple political bargaining model without institutional content and a nonsophisticated or purely legalistic judicial decision-making model. Our results, then, suggest that the Court responds, albeit indirectly, to interest group pressures.