2) The stalking horse scenario
This is a bold move that requires a protagonist to throw themselves under the bus.
This tactic is designed to catch the party by surprise by creating a public crisis that must be resolved immediately.
Former Labor minister Simon Crean opted for this route in 2013, holding a press conference to announce that the leadership speculation between then prime minister Julia Gillard and rival Kevin Rudd had become intolerable and that it must be brought to a head.
Crean went ahead with the plan, but Rudd didn’t go with him (although Rudd denies ever being a co-conspirator). The result was a spill with no challenger.
Julia Gillard remained as PM, but only for another three months – before another snap spill brought Rudd back to the leadership.
3) Cabinet ministers resign
“If my position changes – that is, it gets to a point where I can’t accept what the government is proposing or I don’t agree – then the Westminster system is very clear: you resign your commission, you don’t serve in that cabinet.”
This is how Home Affairs Minister Peter Dutton defined ministerial loyalty in the Turnbull government on Thursday.
A resignation of a senior minister over policy, more than personality, would trigger a crisis of confidence in the ability of the executive to function effectively.
Challenges to Rudd, Gillard, Tony Abbott and John Gorton were all preceded by one or more of their opponents resigning from cabinet.
4) NEG passes the party room but is defeated on the floor of the House of Representatives
The National Energy Guarantee is a battle on three fronts: in the Parliament; inside the Coalition’s own house; and between the Commonwealth and the states.
On Tuesday, Coalition MPs will consider a revamped package which will set the emissions target by regulation, not legislation. The move was designed to appease a block of conservative MPs who are vehemently opposed to enshrining a 26 per cent emissions reduction target in law.
But this allows for a prospect some MPs fear even more: that a future Labor government could increase the emissions target to 45 per cent with the flick of a pen.
If Labor votes against the legislation, Turnbull would be exposed to the threat of arch conservatives crossing the floor to defeat the bill.
5) The PM hangs on but loses the next election
The coming week is as big a test as Turnbull has ever faced. His two signature policies – company tax cuts and the NEG – are up for debate both inside and outside the party room.
A successful week could see him through until May next year, when the next election is expected to be held.
But the government remains behind in the polls and Labor is in an election-winning position, particularly in Queensland, where Dutton and his fellow MPs north-of-the border could watch Turnbull lose the election – and their seats.