Determinants of party cohesion: Evidence from the case of the Israeli parliament

While the parties in the Israeli Knesset (parliament) exhibit relatively high levels of cohesion, similar to parties in other parliamentary democracies, a comparative analysis of party cohesion in roll-call voting across time and among the various parties reveals interesting patterns. First, while the personalisation of politics and the decline of parties over time were expressed also by a dramatic increase in the conducting of roll-call voting, they did not lead to an equally significant decline in the levels of party cohesion. Second, cohesion was relatively high when the voting pertained to issues directly linked to government survival and everyday functioning (the budget, for example); median when it pertained to issues that define parties' identities and coalition potential (namely, security and foreign affairs and religion and state) and relatively low when the vote was on constitutional issues. Third, it was found that the more extremist a party is, the more likely it is to exhibit higher level of cohesion, and that beyond this distinction, left-wing parties are more likely to exhibit higher cohesion than their right-wing counterparts. Finally, the findings demonstrate that - surprisingly - parties' cohesion is generally lower when they are part of the ruling coalition than when they are in the opposition.