In the eyes of one Cabinet minister, today's special Liberal partyroom meeting on same-sex marriage is an exercise in elevating a fifth order issue into a crisis.

Welcome to another day at the office for the Turnbull Government.

The most likely outcome of the meeting is a reaffirmation of a plebiscite, which could morph into a postal vote. That is fraught with problems, some of which were articulated by Malcolm Turnbull in 1997 when the Howard government opted to use the mail to elect delegates to the Constitutional Convention on the Republic.

Then, Mr Turnbull said, the process was designed to disenfranchise migrants, the young, and Indigenous Australians.

"This postal ballot is going to push to the margins of our political society those people who are already on the margins," he said.

Mr Turnbull (right) spoke negatively about the use of a postal ballot when it was used in 1997. ( AAP: Andrew Sheargold )

Then there is the likelihood of a court challenge, a long and tortuous process seemingly purpose-built to keep the distracting talking point at the top of the Government's agenda for months.

That might just suit those in the party who want same-sex marriage to remain, like the soul of an unbaptised child, in limbo for eternity. But that is a small group of zealots.

There is a larger group of Liberals who support a plebiscite and are resigned to the fact that same-sex marriage is an inevitability.

So, if all roads lead back to a parliamentary vote, why delay? Because many MPs and senators are convinced that to shift to a free vote without first being seen trying to honour the plebiscite pledge will enrage the party's already angry branches.

While the postal vote is a bad option, everything else is worse. One minister said that, after a litany of disappointments delivered by the Abbott and Turnbull governments, the commitment to stand by marriage was just about the only thing keeping the party's conservative base in the tent.

The advocates for change are just as convinced that the Government will not get the clear air it so desperately needs until it settles this issue.

So, perversely, both groups believe that they are acting in the best interests of the Government and the Prime Minister.

It is unlikely Mr Turnbull feels grateful. His instinct is for a free vote, but he recognises the political danger of embracing it; particularly as there is a third camp led by Tony Abbott and, for it, every tribulation is amplified as a means to procuring the end of the tenure of the 29th prime minister of Australia.

Plenty of issues for Libs to fight over

Mr Turnbull's frustration at being dogged by this issue was evident at every press conference last week. He repeatedly said it was a media obsession that few ordinary folk raised with him.

The obvious flaw in that defence is the five members on his backbench who were busily giving interviews and drafting a same-sex marriage bill while he was on his tour through Western Australia.

But if it was not same-sex marriage, the Liberals would find something else to indulge their perverse addiction to self-harm. The next ideological battle will be over the Government's response to the chief scientist's call for a clean energy target.

In preparing his report, Alan Finkel noted he was trying to solve what he dubbed the "trilemma": designing policies that simultaneously provide a high level of energy security and reliability, universal access to affordable energy services, and reduced emissions.

"This is easier said than done," Dr Finkel said.

Solving the "trilemma" is no mean feat for Australia's chief scientist, Dr Alan Finkel. ( AAP: Lukas Coch )

One observer recently quipped that, while the Government dithered over a response, there was another trilemma worth noting: that Australia now had the highest greenhouse gas emissions per capita and the most expensive and least reliable energy in the developed world.

Again, kicking the can down the road solves nothing, prolongs the Government's agony and diminishes it in the eyes of the electorate.

No-one can see the future, but there are another three things that seem inevitable.

Same-sex marriage will be legalised and the only way that can happen is through a parliamentary vote.

There will be a price on carbon — or something that approximates one — because without it there will be no investment in new generation.

And if the Government house continues to be divided against itself, it will fall.