Voters constrain government policy through electoral accountability, which depends on how electoral systems interact with party structures. Examining 400 parliamentary elections from 1948-2012 shows that strong party bipartality enables effective voter constraint regardless of the system used.

Bipartality Conditions Accountability

Electoral accountability relies heavily on whether parties form two distinct blocs (bipartality). Our analysis reveals:

* Bipartality is necessary for electoral accountability to function effectively

* Voters can successfully constrain government behavior only when parties are strongly polarized

System Type Impacts Accountability

Interestingly, proportional and majoritarian systems work equally well at enforcing accountability when bipartality exists.

This occurs because:

* Strong biparticle decreases connected coalitions available to incumbents

* Fewer coalition partners mean stronger constraints on policy-making power

Policy Takeaways

Our findings highlight the limitations of electoral reform in parliamentary systems. They underscore that enhancing accountability requires not only changing vote counting rules but also altering party structures.