Saturday’s unprecedented Western Australian Senate election has finally settled the make-up of the chamber’s crossbench after July 1. But Prime Minister Tony Abbott might have a few more weeks to wait until he can be sure of the strength of his government’s hand.

Despite a collective slump in the major party vote, there is a strong possibility that the general thrust of the September election result will be confirmed, with three Liberals likely to be returned along with an uncertain assortment of Labor and minor party members.

However, it is still far from clear that the third Liberal candidate, Linda Reynolds, will indeed emerge victorious when the final votes are tallied; the alternative possibility being that Labor Senator Louise Pratt will scrape home on the back of an improved trend in postal, pre-poll and absent votes.

On the former scenario, the government would require six out of eight crossbench votes to pass legislation when Labor and the Greens lined up against it, and would be well on its way if it could win over a four-person Palmer United bloc that will include the newly elected Zhenya (or Dio) Wang and Victorian Senator Ricky Muir of the Motoring Enthusiasts Party.

Otherwise, the government will only be able to wear one dissenter out of Nick Xenophon, John Madigan of the DLP, Bob Day of Family First, David Leyonhjelm of the Liberal Democrats, and the PUP bloc (assuming the latter holds together).

A strong hand for the crossbench would seem a fitting outcome for an election that gave neither major party anything to crow about, with the Liberals down 5.5% on the September election to 33.7%, and Labor down 4.8% to a dismal 21.8%.

Worse still for the Liberals was that 2% had been freed up by a drop in support for the Nationals, who were down from a high of 5.1% in September when their candidate was former West Coast Eagles star David Wirrpanda.

Nonetheless, it’s Labor that has suffered the bigger embarrassment, as the swing comes off what was already the party’s worst WA Senate result since federation, and the Liberals at least have the excuse that governments usually do badly at byelections. By any standard, a combined major party vote of 58.1% is a remarkable result, given that the equivalent figure of 70.9% from September was without any precedent since the two-party system first coalesced in 1910.

The beneficiaries this time around were not the micro-parties, although their collective total of 13.3% was only slightly down on the September result of 14.5%, and their failure to yield a contender for a seat was mostly down to looser preference arrangements. Instead, the story of the night was the triumph of the Greens and Palmer United, whose candidates easily won election off respective gains of 6.7% and 7.4%.

Scott Ludlam sealed his reputation as one of the Greens’ star performers with a 16.2% share of the vote, marking the fourth occasion the party has secured a 14.3% quota off its own bat, after Bob Brown’s and Christine Milne’s wins in Tasmania in 2007 and 2010, and Richard di Natale’s in Victoria in 2010.

Ludlam’s clear win was a heartening reversal for the Greens after their recent form, although the real lesson to be drawn is that the ebbs and flows in their support are not to be over-analysed either by their champions or their detractors. The inflation of the Greens vote in 2010 mostly represented a negative response to Labor’s leadership disarray and abandonment of carbon pricing, while its weaker showing last year — interpreted by wishful thinkers on the Right as the first stage of a downward plunge to irrelevance — was merely a reversion to type, with perhaps some assistance from the loss of Brown’s personal vote.

The circumstance of a Senate-only election could hardly have been more favourable for the Greens, who had everything to fight for and were unusually well-placed to influence the agenda of a campaign that lacked the presidential aspect of a conventional federal election. As reported in The Sydney Morning Herald last week, advertising monitoring agency Ebuiqity estimated the party’s advertising spend at roughly equal to the combined total for Liberal and Labor, for whom the precise calibration of Senate numbers is a secondary concern.

No less important to the Greens was an energised base of largely tertiary-educated supporters with a high awareness of the election and its importance to the party. By contrast, Labor’s large constituencies of low-income and non-English speaking voters were presumably over-represented among the voters who failed to show up.

A mirror image of the Greens’ success was provided by Palmer United, who are assured of reaching a quota from their base vote of 12.5% (up from 5% in September) thanks to a 4.5% reserve in preferences from sources including HEMP, Shooters & Fishers and Family First. Even more so than the Greens, Clive Palmer was able to put his own stamp on the campaign agenda in lieu of a high profile by the major parties, in his case by promoting Palmer United as a vehicle for a vote against Canberra.

This is always a popular message in WA, and Palmer found an ideal catalyst for it in the state’s ever-dwindling share of GST revenue — together, of course, with the means to propagate it through a reported $477,000 ad spend that dwarfed that of all other parties combined.

A superficial reading of the result might be that Palmer United drew votes from the Coalition parties while the Greens did so from Labor. However, Labor’s research suggests the picture was more complicated, with Palmer United poaching votes in almost equal measure from each side of the major party fence.

In spite of the parlous Labor vote, it follows that some of the 7.5% lost to the Coalition parties resulted from a modest shift of votes from government to opposition, such as byelections typically produce.

Had WA been witness on Saturday to a mere House of Representatives byelection, in which minor parties would have had very little to play for, chances are the result wouldn’t have given electoral prognosticators much to discuss.