Institutions and Vote Unity in Parliaments: Evidence from 33 National Chambers

The paper looks at the relationship between institutions and vote unity in national parliaments with the help of a large data set of votes from 33 national parliaments. The tests run are the first to confirm empirically the relationship between vote of confidence procedure and vote unity. The paper also provides a theoretical explanation for why the existence of the confidence procedure influences vote unity despite being used only rarely. The vote of confidence influences votes through the development of control mechanisms as well as the selection of party members who are more ideologically united. This study also challenges the view that electoral rules which make candidates individually accountable to voters necessarily lead to more vote defections. The findings suggest that higher personal accountability decreases vote unity only if party leaders do not control candidate nomination. Parties that rely on government finance for campaigns are also more united.