There are concerns about the distinctiveness of opposition party behaviour in legislatures, but the literature offers mixed findings. Some point to a blurring of government and opposition (Andeweg 2013), while others find that parliamentary (voting) behaviour remains structured to a high degree by the distinction between governing and opposition parties (Hix & Noury 2016; Loxbo & Sjölin, 2017). Most existing work concerns single-country analysis often for limited time frames. This paper contributes to this debate by analyzing government-opposition distinctiveness in four parliamentary democracies (Canada, Denmark, Netherlands, United Kingdom) over a long time span (1945-2020).

The expectation of a long-term decline of government-opposition distinctiveness is related to increasing levels of party system fragmentation and minority governance, especially in countries with more proportional electoral systems. Decreasing patterns of distinctiveness are expected most clearly among parties with prior governing experience, while challenger parties are expected to behave distinctively.

The country selection offers a diverse set of countries in terms of electoral rules as well as the occurrence of minority governments. In each country, we analyse patterns of parliamentary voting behaviour, in particular opposition party support for government bill, as well as speech making, in particular opposition sentiment. The data collection is based on combining various existing sources of parliamentary data, appended by original data scraping and processing of parliamentary data sources. By comparing these two very different aspects of parliamentary behaviour, we can examine the extent to which there is a difference between distinctiveness in rhetoric and in voting behaviour.