Sizeable Representation? How Constituency Population and Diversity Affects Legislative Behaviour

Do political institutions always exploit their formal powers to the fullest? Models of legislative behaviour in general, and of bicameralism in particular, take as their starting point the constitutional powers of the various actors. We question this approach by studying legislative behaviour in the Australian Senate. Bicameral strength is traditionally measured on two dimensions: The extent to which the powers of the two chambers have the same powers (symmetry), and whether the composition of the two chambers differ (incongruence). However, recent work has suggested a third dimension: Whether the formal powers of the upper chamber are seen as legitimate (Russell, 2013). If fears of perceived illegitimacy are present, upper chambers are unable to use their power fully. The Australian Senate is co-equal with the House of Representatives in terms of all non-financial legislation, and even in the case of the budget, which the senate formally cannot initiate or amend, the Senate takes an active role by ‘requesting’ changes, with an implicit threat of a veto. In terms of composition, the use of a majoritarian electoral system in the lower chamber and a proportional system in the upper chamber, combined with the longer terms and staggered membership renewal of the Senate, means that the government of the day has found itself without a Senate majority since 1956 (with the exception of 2005-2007). As such, in terms of both symmetry and incongruence, the Senate scores highly. However, the Senate is often seen as having limited legitimacy in terms of using this power to prevent the government and its majority in the House of Representatives from governing. This combination of formal power, near-constant opposition control of the Senate, and limited legitimacy creates a substantial conundrum for the Senate, as maximally exploiting its constitutional powers may lead to a backlash. However, one role of the Senate that is widely seen as legitimate, even by the members of the lower chamber, is to function as a “house of review” – to keep the government of the day accountable. This is also the role that the majority of Senators see themselves as being primarily entrusted to perform. Analysing the variations in timing of parliamentary questions from the Senators (review/accountability) and amendments proposed (policy-making) over a 30-year period, and combining this with interviews with serving Australian senators, we show that the risk of potential claims of illegitimacy damaging a senator’s party in the run-up to elections leads to senators focussing on review rather than policy-making. As such, we show that models of bicameral power need to include the potential for upper chamber members to be unwilling to fully exploit the powers at their disposal.