Explaining Opposition Parties’ Voting Behavior in Parliament

For voters to have a meaningful choice at elections, opposition parties should behave distinctively different from governing parties in parliament. This paper examines the factors that affect whether opposition parties vote in favor of or against the government in parliament. Previous studies included only a single parliament, employed a case selection that was not theoretically informed, and/or focused on a limited time frame reducing the variation in government characteristics. Furthermore, the number of empirically tested explanations of opposition behavior across countries, governments, opposition parties, and bills remains limited. We know particularly little about how the topic of the legislation at hand affects the voting behavior of opposition parties. This paper brings various explanations together in a single framework, proposing that opposition parties are motivated by policy preferences, office aspirations, and electoral incentives. The analyses do not focus merely on structural differences between parties, but also on how contextual differences between parliamentary votes – e.g., the policy domain of legislation – affect opposition parties’ behavior. Data on parliamentary votes during 1945-2020 are employed to test the expectations in four established parliamentary democracies with very different political systems: Canada, Denmark, the Netherlands, and the United Kingdom.