Erik Moberg ã:
A Theory of Democratic Politics
6.4 - MEANS OF DISCIPLINE RELATED TO PARLIAMENTARISM
According to the fourth hypothesis there is also another mechanism of discipline, which is related to parliamentarism rather than to proportionalism. This mechanism has been discussed now and then since long.
Gary Cox (1987, p 80 ff) thus gives an account of an interesting discussion in which Walter Bagehot (1826-77) notices and explains the discipline of the British parties. According to Bagehot the legislators were afraid of voting against the executive, since thereby, through the dissolution of the Parliament, they might lose their places there. This explanation was however refuted in the discussion on the ground that it did not explain the cohesion of the opposition party. Duverger gives a slightly different version of the same argument when he asserts (1964, p 404) that the British government often uses the vote of confidence, and thereby the threat of dissolution, and a new election, as a disciplinary weapon within its own party. Later still Shugart & Carey write (1992, p 173) that "Where parliamentary systems have become fully developed, the existence of the institution of the vote of no-confidence has mandated an imposition of discipline. This party discipline in an archetypal parliamentary system (such as the United Kingdom, New Zealand, or Norway, for example) is sure to be far stronger than in a typical presidential system's assembly ... ".
Obviously there may be a mechanism like this, even if it also seems correct that it does not explain the discipline of opposition parties. But perhaps the discipline of the opposition, in parliamentarian and majoritarian systems, really is lower than that of the party, or parties, in power.
Anyway, there is an interesting and important difference between the means of discipline discussed here and those related to proportionalism treated in part 6.3. The difference is that the latter are discriminating in the sense that they could be used against a single legislator or candidate, whereas those discussed here are non-discriminating and usable only against the governing party's parliamentary group as a whole.