As the clock runs down on the campaign for Saturday’s unprecedented Western Australian Senate re-election, the outcome gets no easier to predict.

The only candidates who can rest entirely easy over the next few days are the two who head the Liberal ticket — David Johnston and Michaelia Cash — and the top Labor candidate, Joe Bullock. Remaining in limbo are incumbents Scott Ludlam of the Greens and Labor’s Louise Pratt, together with third Liberal candidate Linda Reynolds, who emerged the biggest loser out of the September fiasco after her clear victory in the original count had to be overturned.

No published polling for the Senate election has emerged to light the way, and even if it had there would be cause to treat it with caution.

It is agreed turnout will be low — as low as 60% to 65%, if David Johnston’s estimate is to be believed — and while this intuitively sounds most dangerous to Labor and the micro-parties, the precise impact is hard to predict.

Some guide at least is offered by state-level breakdowns of federal voting intention from the published pollsters, which when run through the BludgerTrack poll trend model show the Coalition on 45.5% (down 5.7% on the election), Labor on 31.2% (up 2.4%), the Greens on 11.9% (up 2.2%) and Palmer United on 5.9% (up 0.6%).

Even after accounting for the lower vote share typically recorded by major parties in the Senate, this suggests the established parties are strong enough to produce a traditional result of three Liberal, two Labor and one Greens, with no repeat of last year’s micro-party boilovers. However, the difficulty with these figures is that they are derived from a trend calculation and thus slow to respond to short-term developments.

An advertising juggernaut has steamrolled voters over the last fortnight courtesy of Clive Palmer, who looks to be repeating his feat of last September in spending his way into contention over the final weeks of the campaign. Some of the most recent results from WA show Palmer United breaking into double figures, and while the samples involved are uniformly small, the numbers are impressively consistent in having the party at or near 10%.

The Liberals particularly are devoting more energy than they would like to fighting off the Palmer insurgency, but it’s far from clear that their efforts are doing him more harm as good.

The West Australian has made Palmer the cover star twice this week, and while the reports themselves were highly unflattering, Palmer might well be of a mind to regard any publicity as good publicity. While similar efforts by Palmer failed to yield any dividends at the recent Tasmanian election, he seems considerably more at home making his pitch to the nation’s leading mining state.

His television advertising has adroitly tapped into deeply held grievances about the state’s share of GST revenue, a subject the major parties dare not go near for fear of alienating voters in other states …

Should Palmer United achieve its breakthrough, the question arises as to whether its win will be at the expense of the Liberal or the Labor-Greens side of the equation. To win a seat directly at the expense of Linda Reynolds would require that the near 40% gap that separated the Coalition (44.3%) from Palmer United (5.0%) at the September election be reduced to more like 30%. The easier path involves Palmer United winning a seat in addition to Reynolds, again leaving Scott Ludlam and Louise Pratt fighting over the second seat on the Left.

While some commenters have been taking a second Labor seat for granted, Ludlam would not be without his advantages in such a contest. Not the least of these is the fundamental importance to his party of a strong hand in the Senate balance, which is causing it to throw everything it has into the campaign. Its television advertising has been at least a match for the major parties in terms of volume, and its content suggests the party is confident it can sell left-wing Labor supporters on the idea of a personal vote for Ludlam.

An alternative scenario that has been widely canvassed involves Palmer United bowing out during the count and its preferences contributing to another micro-party boilover. Preference wonks have been particularly enthused about Help End Marijuana Prohibition, which has dealt its way high on to the preference orders of such unlikely concerns as Shooters & Fishers and Katter’s Australian Party. However, the prospects of such an outcome diminish with each vote gained by Palmer United.