Despite concerns about the prominence of partisan polarization and legislative dysfunction in Washington, the national policy making process continues to demonstrate a considerable degree of variability in process and outcomes. Although the process is dominated by partisan politics under some conditions, it continues to reflect norms of technical experts, the influence of interest groups, or the demands of populist sentiment in others. While some policies become stuck in partisan stalemate, others race through the process at breakneck speed. Once enacted, some policies are sustained and institutionalized while others remain susceptible to further change, retrenchment, or reversal.

In explaining the underlying political processes giving rise to this volatile flux, this paper builds on earlier work which developed a framework for explaining policy diversity. That research developed a typology of four distinct policy making pathways or regimes: pluralist, partisan, expert, and symbolic. Each of these distinct regimes draws upon different political resources, appeals to particular actors in the system, and elicits its own unique strategies and styles of coalition building.

In this paper, we go beyond the discussion of individual pathways to consider how the framework can improve understanding of policy evolution and change. Using a longitudinal perspective, we identify 42 significant legislative enactments or proposals in eight discrete policy areas over the past 30 years. We use the pathways framework to assess the underlying political mobilization approaches and styles giving rise to policy change and also attempt to gauge how shifts in the pathways at work help us to understand shifts in policy outcomes. In particular, we find that the pathways differ systematically in terms of agenda setting and the origins of policy alternatives, levels of political salience and conflict, policy sustainability, and patterns of policy evolution and change. The framework is also useful for understanding the secular shifts that are underway in the types of mobilization strategies deployed by actors in our political sy