This study examines how institutional context shapes voting in legislatures.

Data & Methods: Roll-call voting data from 16 parliaments were analyzed using geometric scaling metrics and statistical vote-by-vote analysis. The research compared government-opposition dynamics with parties' left-right policy positions across different political systems.

Key Findings: Government interests drive most voting behavior, resembling Westminster parliamentary systems. Single-issue coalition building along a left-right dimension only occurs under specific institutional conditions: presidential regimes or minority parliamentary governments.

Why It Matters: The findings suggest that government-opposition relations are more significant in driving legislative outcomes than parties' ideological stances across different political systems.