Caucus solidarity in Britain, Australia and the US

Tony Blair has been defeated on religious hatred legislation after a backbench rebellion. Revolts.co.uk details the story and provides comprehensive information on party revolts. These never happen in Australia (recently anyway), Senator Joyce being the only very minor exception. This is often seen as result of Labor’s early commitment to caucus solidarity and the emulation of this by the conservatives. But if you look at the early versions of the Labor pledge in NSW here it was more open, even the 1893 NSW Labor pledge which lead to a major party split specified criteria (although broad) to determine what votes were caucus bound and the 1895 compromise pledge required caucus voting on matters affecting the Labor platform and the fate of the government. The caucus split on the premiers' Plan can probably be classified as extraordinary circumstances but Sawer notes in passing that some Labor members in 1930-31 voted against tariff increases (p. 29). True Believers notes that the first federal Labor caucus was only bound on Platform questions (p. 31) but I don't think it explains anywhere how caucus solidarity was extended to all legislation. Now it is absolute and even the Labor factions in student politics have adopted it, at least when I was about (for this student politics in practice with its Comintern style hysteria see here).

Two points: 1) this is a gap in Australian political history; 2) would the ALP benefit by a British-style approach that enabled MPs to revolt? Some would hopefully anticipate inner-city Labor MPs rebelling on social liberalism i.e. asylum-seekers against a pragmatic leadership, but on the other hand the failure of American unions to get ‘their' party' (the Democrats) to support labour law reform suggests that caucus dissent could be to the right as well as the left.