And like many a marriage, their performance on the day could go a long way to determining whether this will be a long and fruitful matrimony, or a brief candle whose initial flame of enthusiasm is doomed to quickly sputter out.

So no pressure, Rob.

But if the Marshall Government’s own 100-day milestone back in June didn’t mark the self-imposed end of the honeymoon, it’s evident that by day’s end tomorrow, the honeymoon will be well and truly over.

Because we will, finally, have a costed document that lays out – for better or for worse, for richer or for poorer – just what kind of government we have shacked up with.

There will, no doubt, be some tough love.

After all, the foreplay has been naught but talk about how “tough” the budget will be. Tough, but fair, obviously.

Which is, by and large, just how governments assume we like our budgets.

Although, as the moment approaches, a more chastened Treasurer has been forced to confess to the “modesty” of his surplus.

But, as we know, it’s not what you’ve got, it’s what you do with it that counts.

And in that vein, tomorrow’s budget will outline what the Marshall Government wants to do with its (first) four years in office, and how it intends to pay for it.

Which in itself is kinda extraordinary.

Because the whole principle underlying Marshall’s long-held philosophy of government is that major spending and economic decisions will be subject to the rigours of independent panels –which have yet to be established.

The Government’s moment of consummation will not deliver a ‘big bang’

What this means, then, for the roles of the oft-spruiked Infrastructure SA and SA Productivity Commission once they are finally up and running is unclear. Can they retrospectively shelve announced projects that don’t meet their criteria?

Or do they merely pick things up from wherever they are currently at?

Are we to assume that any infrastructure spending allocated before Infrastructure SA kicks off is neither “properly researched” nor “methodically implemented”, as per Marshall’s imperative for establishing it in the first place?

Perhaps not.

But tomorrow’s document – the bits, at least, that haven’t already been strategically announced to the media, primarily through friendly ‘drops’ to the Government’s favoured News Corp-owned community message-board – will also be noteworthy for another reason.

It will, essentially, spell the final political legacy of Treasurer Rob Lucas.

The parliament’s longest-serving MP will bow out at the next election, and will presumably hand over the Treasury reins at some point before that (unless the Government thinks it’s a good idea for all the economic questions in the campaign lead-up to March 19, 2022 to be fielded by someone who will be sailing off into the sunset on March 20).

So this, his first four-year economic statement of the Government’s term, essentially represents what Lucas has waited for 16 years to introduce.

Every snipe across the chamber, every lament about Labor’s economic mismanagement, every wistful thought about how the Liberals could and should do things better: it all manifests itself in the ungainly stack of budget papers that will be handed down tomorrow.

Lucas could be forgiven for wanting to lay it all out. To dramatically overhaul the levers that turn the SA economy.

After all, his philosophy on the public sector is no secret. In 2006, he pledged to fund his party’s election promises by taking a bulldozer to the public service, with 4000 jobs on the block – a policy even he conceded would hit the unemployment rate.

This didn’t appear to go down well at the ballot box, although given the state of the SA Libs at the time, it’s unclear how much of that year’s ‘Rannslide’ can be attributed to any given policy as opposed to their general crappiness.

But we also know that Marshall’s invited political gurus – and by extension, Marshall himself – don’t favour the ‘crash-through-or-crash’ approach.

Long-time New Zealand National Party strategist Wayne Eagleson has warned the fledgling SA Government that reform should be “done over three terms rather than a ‘big bang’”.

The caveat being, I suppose, that you must be elected for three terms first.

Still the message is clear: the Government’s moment of consummation will not deliver a ‘big bang’.

We can, perhaps, blame performance anxiety, with the administration clearly worried about the length of its, um, term.

But Marshall – and others – well learned the lesson of Campbell Newman in Queensland. In essence, the new economic mantra for state Liberals is the opposite of that old foreign policy diktat to “speak softly but carry a big stick”.

Here and now, we speak loudly, but do very little about it.

Mind you, if it’s premature for the new government to outline an agenda that, by their own strictures, should be subject to the oversight of independent panels that do not yet exist, some of the Marshall rhetoric is becoming decidedly long in the tooth.

Having campaigned on its ability to deliver a ‘better working relationship with the Federal Liberals after years of Labor infighting with Canberra’, the theme was being rolled out again as recently as yesterday, with Commonwealth cash being “fast-tracked” (whatever that means) for pre-promised SA projects.

Of course, recent developments within the Federal Liberal partyroom, and the consequent opinion polls, suggest this ‘we can get things done because we’ve got friends in Canberra’ line might not have a long shelf-life.

As of mid-next year, the dynamics could well be very different. Marshall would do well to turn his mind to how he intends to handle the political dynamics of a prospective Shorten Labor Government.

It could be no bad thing: Jay Weatherill’s political capital, after all, was built on his spats – both real and invented – with a federal foe of a different political hue. While for that same period Marshall’s opposition, more often than not, was stuck between the rock of federal fractiousness and the hard place of partisan loyalty.

In some ways, Marshall could be liberated by having an ideological foe in Canberra – but that he has built his temple on his preferred predilection for consensus.

In any case, the second year of Marshall’s Government could be played out in a very different environment to the first.

Once Infrastructure SA and the Productivity Commission come into play, spending priorities could look very different – as could the willingness of the Commonwealth to fund them.

It’s feasible to imagine a wistful Lucas, in years gone by, dreaming of the things he might do with his first budget after so long in the wilderness.

But the quiet tempo of this administration so far suggests a far more ‘steady-as-she-goes’ approach. Even the pre-budget drops have been little more than a checklist of pre-election pledges being allocated enough funding to proceed another step.

So it’s entirely possible that tomorrow’s consummation of the electorate’s relationship with the government it elected back in March will be little more than the realisation of those whispered wedding-night promises – perhaps with a few pet peccadilloes from our former Labor squeeze banished from the boudoir.

It’s a fraught gambit. SA is an electorate, after all, that is accustomed to marrying for money.

But if the Marshall Government’s first budget foray leaves us feeling a little less than satisfied, that’s probably better than the alternative.

We could, after all, just be left feeling screwed.

Tom Richardson is a senior reporter at InDaily.