Managing coalition government in an upper house: testing the `keeping tabs' theory in the House of Lords 2010-15

Can an upper chamber in a system accustomed to single-party government be used by political parties to manage their involvement in coalition government? This thesis answers this question by examining the 2010-15 coalition government between the Conservatives and Liberal Democrats. A principal-agent problem associated with coalition government raises the prospect that ministers will shift policy away from agreed policy positions. In recognising this, a body of work has grown around how parties in coalition manage this tension. The theory of `policing' proposes that government backbenchers will use features in the legislative process to keep tabs on their partner ministers (Martin and Vanberg 2011). We build on this theory by proposing that backbenchers will use mechanisms in the House of Lords to police ministerial behaviour in areas where there is greatest intra-coalition policy tension. By analysing three unique quantitative datasets, we show that government backbenchers participated in greater numbers in debates on bills as policy disagreements grew. Likewise, legislative amendments were strategically targeted at ministerial proposals in more contested areas. We also show that policing behaviour carries over to the policy implementation stage, where parliamentary questions are used for this purpose. In the process of testing these expectations, we outline a preference based theory of behaviour in the House of Lords based on policy-seeking incentives.

We support this theory with evidence that members of the Lords focus their political behaviour on policy areas in which they hold professional experience and expertise.