In organisational terms, the ALP has always been closer to the British Labour Party (BLP) than just about any other national political party.
Both are 'labour' parties in the formal sense, meaning that they were established by trade unions and unions are privileged internally over other groups and individual branch members (through formal affiliation).
The 'labour' model of party-unions links is very different from that which is found in the US Democrats.
There is much more on this stuff in my thesis.
In recent decades, leaders of the ALP and BLP have seen party reform (usually meaning reducing the influence of unions) as part of their strategy to lead their parties back into government.
The reason is obvious. Social, economic and technological changes have reduced significantly the political relevance of unions.
No aspiring PM can afford to be seen to be beholden to unions and union bosses.
Rudd's proposal to give branch members a say in electing the parliamentary leader aims at two purposes: it reduces the influence of caucus factional leaders and it reduces the influence of union bosses (because it does not give unions a privileged position in the voting).
In addition, Rudd has made some sensible but not particularly important reforms to clean up the embarrassing NSW branch.
Yet, these changes are well behind the ambitions of Britain's Opposition Leader, Ed Miliband.
Miliband proposes (see here and here) that non-party members should be able to vote in party elections, and that its three million union political levy payers can only be involved in the party if they choose to.
These proposals would take the BLP away from the 'labour' model and move it much closer to the US Democratic party model.
Miliband wants the BLP to be (again?) relevant to the lives of ordinary working people.
Australia has this problem too. Rapid declines in party membership and union densities (proportion of workforce that is unionised) have given union bosses, MPs and factional operatives more power than ever before.
Labour parties have lost the sense of being a movement.
Miliband wants some of that movement energy and enthusiasm back.
Part of this I think is a realisation (partly flowing from Obama's success) that good campaigns actually need people not just focus groups and good advertising,
Some union leaders in both countries will resist the diminution of their own power, smarter ones will recognise that being in government is worth it.
Already, I think we can see that Rudd's reforms so far are a step in a longer process.