Samara (reference below) defines party discipline as the ability of party leaders to ensure party members’ support their policies in Parliament through various means, including control of MPs’ nomination for election and membership in the caucus and their assignment to various party and parliamentary roles.
The Wikipedia article on party discipline notes that:
“Breaking party discipline in parliamentary votes can result in a number of penalties for the member who dissents. These penalties include not being promoted to a cabinet position, and losing other perks of elected office like travel. … Party discipline tends to be extremely strong in Westminster systems such as the United Kingdom, Canada, Australia, New Zealand and India in which a vote by the legislature against the government is understood to cause the government to “collapse,” according to the convention of confidence votes. In these situations, it is extremely rare for a member to vote against the wishes of their party. Party leaders in such governments often have the authority to expel members of the party who violate the party line. … In countries such as New Zealand, which use an MMP (mixed-member proportionality) system of voting, party discipline tends to be high. This is especially true for list MPs, who do not represent an electorate. If they do not vote the party line, they risk being demoted on the list in the next election and not returning to parliament.”
Atlas topic, subject, and course
Samara, Glossary, at http://www.samaracanada.com/samara-in-the-classroom/electoral-reform/glossary/, accessed 25 August 2016.
Wikipedia, Party discipline, at https://en.wikipedia.org/wiki/Party_discipline, accessed 25 August 2016.
Page created by: Ian Clark, last modified on 25 August 2016.