One of the great pleasures of the Australian Constitution is its observation of the proprieties. For example the Prime Minister is not mentioned. This might seem odd but the constitution is drafted in such a way as to give rise to the Westminster system. It does not explicitly state all the rules – with the scope for endless quibbles based on infelicitous wording to which that would give rise – instead, the unwritten rules are simply imported into our system.
It is noticeable that in the letter dismissing Gough Whitlam as PM, Sir John Kerr never uses that title. He simpy refers to "my Chief Adviser and Head of the Government" and he could probably have dispensed with the capital letters. The Westminster system of a Constitutional Monarchy simply presumes that some member of Parliament has the right to provide exclusive advice to the Governor General (who exercises all the powers of the Crown) which is practically (but not necessarily) binding.
But which member of Parliament? For starters the Constitution does insist that nobody can be a Minister for more than three months "unless he is or becomes a senator or a member of the House of Representatives". Well the Westminster system is whoever controls the highest number of votes in the Lower House, i.e. the leader of the party with the most seats in the House of Representatives is appointed Prime Minister. This is because the Lower House controls spending. The Crown, since the English Civil War, is not allowed to raise or even spend money without the consent of Parliament. If you want to have this channel of exclusive advice to the Crown, the Crown wants something in return. It wants you to be able to secure spending. In other words to keep the country going.
In Australia there is a wrinkle in that the Upper House, the Senate, cannot originate money bills – but it can hold them up indefinitely. This is what happened in late 1975 when the Senate (controlled by the opposition) refused to pass the legislation for the government's spending. This meant that the Prime Minister, the leader of the ALP, which had the highest number of seats in the House of Representatives, in fact could not secure the Crown's power to spend money. In the jargon, the PM was no longer able to "guarantee supply". Hence he was dismissed.
In the UK this power of the Upper House was removed by the Parliament Acts, which for some reason Australian crown-haters, and other Whitlamite whingers, think applies in Australia. If it did then the Senate's refusal to pass money bills in 1975 would have been unconstitutional, and the dismissal of Gough Whitlam an outrage.
One other happy aspect of the Australian constitution is its failure to acknowledge the existence of those blights on political life, the parties. At least it was until 21st May 1977 when a referendum was passed to change section 15 of the constitution "to ensure, as far as practicable, that a casual vacancy in the Senate is filled by a person of the same political party as the Senator chosen by the people".
Note those words "the same political party". In Australia we do not just have parties but factions – parties within parties – as well. These factions are more or less formally recognised in internal party affairs. Each faction gets to control such and such a proportion of the party's activity, depending on its strength. In March 2012 Bob Carr, former Premier of New South Wales was appointed by the State Governor, on the advice of the Premier of New South Wales Barry O'Farrell, to fill a casual vacancy in New South Wales' representation in the Senate. It did not matter that Mr O'Farrell is a member of the Liberal Party and Bob Carr is in the ALP. Had the Premier advised the appointment of a fellow Liberal, the Governor would have been entitled to refuse such advice because of the amendment to section 15. Bob Carr took up the Senate vacancy to enable him to fulfil a lifelong ambition and be Australian Foreign Minister. If you think that sounds cynical, that is because it is.
There was a Federal election in Australia in September this year and Mr Carr's party was turfed out of office. He however kept his seat. Nevertheless the duties of opposition do not appeal to Bob and so he is going to resign his seat. (Actually he is going to resign twice, but that is another story.)
BOB Carr will resign from the Senate without sitting again in parliament, with the NSW Labor Right expected to nominate one of its defeated MPs as the former foreign minister's replacement.
The "NSW Labor [sic, that is how the ALP spells its name] Right" is not a political party, but a faction within a political party. It would be perfectly legal for the Premier to advise the appointment of someone from the left faction or whatever. But he won't.