If numerous successive polls are to believed, next month South Australia will have its third Premier in as many years.

The campaign proper doesn’t kick off till tomorrow, but already this week Labor has committed $160 million within four years for a tunnel under Hackney Road and North Terrace to extend the O-Bahn, a quirky piece of Tonkin-era investment once derided by sometime Infrastructure Minister Pat Conlon as “one of the most expensive forms of public transport ever invented”. (The quote is from The Tiser, November 24, 2004, and I can vouch for the article ‘cos I wrote it.)

Given one of Jay Weatherill’s primary attacks on the Opposition is the promised expenditure it’s racking up (Labor’s alleged $949 million figure compiled, incidentally, with gleeful ignorance of any Government accounting methodology), it seems an odd gambit to start campaign week tens of millions of dollars in arrears and with no real explanation of where you’ll find it.

“We can reprofile some other projects,” he explained rather lamely, and when pressed refused to clarify which projects he might have in mind for reprofiling, which is, apparently, a clever Government code for “scrapping”.

Labor appeared to have some traction coming into the New Year, but it appears the cliché that Oppositions do not win elections, rather Governments lose them, is likely to be proven true once again.

Perhaps spooked by its own vague costings and underwhelming fiscal position, Labor has lost track of its own narrative in this Clayton’s campaign. It had thus far been the party to outline a vision of sorts, while the Liberals have simply pointed to 12 years of Labor failure; and yet last week the Premier took to the stage in front of more than 600 business leaders for a debate with Steven Marshall, and rather than emphasising Labor’s commitment to a new Women’s and Children’s Hospital or a Transport Plan, he launched a forensic defence of Labor’s term of Government. It wasn’t Weatherill’s own narrative, but rather a counterpoint to Marshall’s, and that suggests the Liberals are now setting the tone of this campaign. Twelve Years of Labor Failure. The more Weatherill defends this point, the more it will resonate. And then he is lost.

There is still to be much waxing and waning of electoral fortune as the next four weeks unfold, but Labor is now hoping for too many variables to fall its way. That, like in 2010, the swing will not be uniform. That Chloe Fox can actually manage a swing to, rather than against, despite having been handed a volatile portfolio in an electorate that has felt that portfolio’s failures most keenly. That Tom Kenyon can repeat his remarkable individual result in Newland, and that somehow his triumphal response to that result – a rousing refrain of “We F***ed ‘Em” yelled from the stage at the ALP election-night after-party – won’t show up in any Liberal campaign ads.

That conservative independents will deny the Libs an outright majority and, against their natural inclination, be persuaded to prop up an ageing Labor administration. That Tony Abbott’s dogged free-marketeering will play badly for the Liberal brand against Labor’s unabashed paternalism. That Steven Marshall, the hot-headed, untested rookie leader will spectacularly implode in the heat of battle.

All valid propositions, but thus far it is only the ALP that has imploded, and the slight spring in Labor’s step as it farewelled a difficult 2013 has vanished as the party sinks into a political mire largely of its own creation.

If things continue in this way, then, yes, we will have our third Premier in as many years next month, and Weatherill’s brief candle will be extinguished as his battle-bruised party wanders blindly into the darkness of Opposition.

So it’s worth asking: just what do we know about this Steve Marshall fellow?

It’s a question I get asked a lot by people with a blissfully passing acquaintance with state politics. By people who might have shared a handshake and a quick word with the Premier and Opposition Leader, and were struck even in that brief exchange by the contrast – the dour, serious, taciturn Weatherill and the gregarious, jovial, indiscreet Marshall.

So what do we know about him?

We know that he works hard, and is driven.

We know that he was born into business, and has made a fair success of it.

We know that he frequently wakes up not all that long after many of us go to bed, in order to balance work and family commitments.

We know that he dresses – or is dressed – with care, paying due deference to expensive labels.

We know that he is not a natural politician; he was conscripted to the Liberals as an aspiring candidate.

We know that you can yell at him a bit, even on his birthday, and he’ll still front up to his next media conference and deal with you courteously.

We know that he has the capacity to be politically ruthless, given that he helped Martin Hamilton-Smith move against Isobel Redmond, who had helped him into parliament and then promoted him swiftly.

We also know that despite this he still retains a close and friendly relationship with Redmond.

We know that he’s the man most likely to be running the state in four weeks and one day’s time. What we don’t know is what kind of premier he’d turn out to be then. Even Steven Marshall doesn’t know that.

 Tom Richardson is InDaily’s political commentator and Channel Nine’s state political reporter.