Spatial models of lawmaking predict that the configuration of legislative pivotal actors and presidents' constitutional powers (decree, veto, and agenda authority) determines how far and how often policy moves away from the status quo. Crisp, Desposato, and Kanthak (2011) formalized this logic across the institutional variety of presidential systems, simulated predicted policy behavior, and tested the predictions against data capturing economic policy choices in Latin American democracies; the cross-national test yielded a null result. Whether that null reflects a genuine absence of the institution-stability relationship or artifacts — measurement error in ideal points and status-quo locations, low statistical power, constitutional entrenchment, vote-buying, and external reform pressure — remains unresolved. Later work advanced pieces of the agenda (common-scale measurement of preferences and policies; institutional determinants of policy volatility via aggregate ratings) but no study has re-tested the pivot/power-configuration predictions for policy stability with valid measurement and adequate power. The problem is to determine whether, and in what functional form, veto structure maps onto policy stability in presidential systems.

Background

Most democracies outside the United States combine a directly elected president with an independently elected legislature — presidential systems with a strict separation of powers in which neither branch can depose the other. Whether policy in such systems changes a lot or a little — policy stability — is a central question of comparative political economy: highly volatile policy (frequent reversals of taxes, tariffs, and regulation) depresses investment and growth, while gridlocked policy fails to adapt to shocks.

Two spatial-modeling traditions predict policy stability from institutional structure. In spatial models of lawmaking, politics is reduced to the positions (ideal points) of actors along a policy dimension such as left–right, a fixed starting position (the status quo), and institutions that determine whose consent is needed to move policy. Pivotal politics — the US tradition initiated by Keith Krehbiel and reviewed in Krehbiel (2018) — predicts that policy changes only when the status quo lies far enough from pivotal actors such as the median legislator or the veto-override majority (the smallest coalition able to enact policy over a president's objection); the set of status quos that cannot be moved is the gridlock interval. Veto players theory (Tsebelis 2002) generalizes the idea: a veto player is any individual or collective actor whose agreement is required for policy change (a chamber, a president, a constitutional court), and more veto players with more divergent preferences imply greater policy stability. Related formal work extends these models to divided government with party discipline (Colomer 2005) and documents how Latin American constitutions vary in the veto and decree powers they grant presidents — decree power being authority to issue binding policy unilaterally (Alemán and Schwartz 2006); Johnson and Crisp (2003) analyze how electoral mandates and presidential powers translate into policy.

Crisp, Desposato, and Kanthak (2011) — hereafter CDK — brought these US theories to the institutional variety of presidential systems. They formally model the legislative process across presidential regimes that differ in decree powers, veto powers, and legislative party systems; simulate the policy behavior each institutional configuration implies; and test the predictions empirically against data capturing economic policy choices in Latin American democracies, the region with the widest variation in presidential powers. Their cross-national test failed to confirm the theoretical predictions: observed policy stability did not vary across institutional configurations in the way the pivot/veto-structure models predict. The conclusion offers candidate explanations rather than a resolution: measurement error in legislators' and presidents' ideal points and in the location of policy status quos, which could bias estimated institutional effects toward zero; limited statistical power (59 regime observations from 17 countries over 1985–1999), with better within-country leverage available after constitutional reforms that change decree and veto powers; constitutional entrenchment, since many economic policies in Latin America are embedded in constitutions whose amendment requirements raise the cost of change independently of ordinary legislation; vote-buying and pork-barrel politics that break the unidimensional spatial logic; international pressure for structural reform during 1985–1999, which may have overwhelmed domestic institutional incentives; and the models' assumptions of myopic (one-shot, forward-looking-free) players and a unidimensional policy space.

The adjacent literature gives the question bite. Using aggregate institutional ratings rather than pivot locations, Pereira, Singh, and Mueller (2011) find that Latin American countries with simultaneously strong executives and weak legislatures have unstable policy environments, as do countries with unified government — so institutional configurations do relate to policy stability in some form. Doyle (2014) shows that natural-resource rents raise policy volatility in 18 Latin American economies where political institutions fail to support intertemporal agreement. Kim (2014) finds that the number and ideological positions of veto players shape economic-reform efforts across developing democracies. The veto-player program remains empirically active in other settings (König, Debus, and Tsebelis 2011). What is missing is the pivot-theoretic test itself: whether the specific configuration of pivot positions and presidential powers, measured on a common cross-nationally comparable scale with policy status quos, predicts the magnitude of policy change. The measurement infrastructure now exists — Bayesian common-scaling of mass and elite preferences and policy positions across 18 Latin American countries in Crisp, Olivella, and Rosas (2020), and Monte Carlo evidence in Hirsch (2011) that ideal-point-based tests of pivot theories are not inherently biased — but it has not been turned on the stability question.

Problem Statement

Determine whether, and in what functional form, the configuration of legislative pivotal actors and presidential constitutional powers in presidential democracies determines policy stability — the magnitude and frequency of change in policy status quos — as spatial models of lawmaking predict, addressing the candidate explanations for the null cross-national result of Crisp, Desposato, and Kanthak (2011). Resolving the question requires: (i) valid measurement — ideal points of presidents and pivotal legislators, locations of policy status quos, and realized policy outcomes estimated on a single, cross-nationally comparable scale, so that pivot-status-quo distances are meaningful across countries; (ii) a test with adequate statistical power to distinguish the models' directional predictions — the status quo lies inside the immovable gridlock interval when it is not far enough from the relevant pivots, while weaker agenda or decree powers should yield smaller or less frequent policy change — from noise; and (iii) adjudication of the confounds the source enumerates — constitutional entrenchment through amendment requirements, vote-buying and pork-barrel incentives, and external reform pressure — so that a null result can be attributed to the absence of the relationship rather than to attenuation or confounding. The source also notes that its models assume myopic (one-shot, forward-looking-free) players and a unidimensional policy space; whether these assumptions contributed to the null is open to assessment. At issue is whether the pivot/power configuration predicts policy stability, whether an observed absence of relationship is genuine or an artifact of measurement and statistical power, and which mechanism — pivot structure, executive dominance, or the enumerated confounds — drives the observed pattern.

References

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