In the clear air that has followed last month’s leadership coup, the outline of a resolution to the vexed question of Senate electoral reform may be coming into view.

Since the Senate holds the key to its own reform, two of its crossbench members are emerging as key players, should the government choose to proceed.

Over the past few weeks, separate new proposals for reform have been advanced by independent Senator Nick Xenophon and Liberal Democratic Senator David Leyonhjelm, who are bitterly opposed on the fundamental point at issue.

Xenophon was perhaps the single most aggrieved party of the 2013 Senate election, at which his ticket scored 24.9% of the vote in South Australia, but failed to win a second seat due to his refusal to engage in preference horse-trading.

By contrast, Leyonhjelm has been an unapologetic player in the preference games characteristic of the existing system, having involved himself directly in numerous micro-parties whose main mission was to feed preferences to each other.

That Xenophon and Leyonhjelm have both adopted new positions reflects the shifting terms of the debate since last year’s report of the Joint Standing Committee on Electoral Matters, which recommended an optional preferential voting system with the unanimous backing of Coalition, Labor and Greens members.

Leyonhjelm had hitherto held the reform project to be nothing more than a bid by the big party cartel to freeze out new competition. His new position presumably reflects a calculation that reform is coming in any case, and he is best served by ensuring that it happens on favourable terms.

Xenophon’s shift likewise represents a change of tack since a private members’ bill he introduced shortly after the election, which offered essentially the same deal that JSCEM would propose six months later.

On the surface, the differences between the three proposals may appear rather subtle. Each gives voters the option of having their vote drop out of the count at the point where they indicate no further preference, in contrast to the present system where all votes remain until the bitter end (with minor exceptions).

Furthermore, none of the three proposals would change the design of the ballot appear, which would continue to offer an above-the-line option for those who aren’t interested in distinguishing between the parties’ candidates, and many more boxes below the line for the few who are.

Under the JSCEM proposal, voters would be free to number as many or as few boxes above the line as they desire, while below-the-line voters would have to number as many boxes as there were seats up for election — six at a normal half-Senate election, 12 at a double dissolution, and two in the territories.

Xenophon’s latest plan tweaks that to a minimum of three boxes above the line or 12 below it, so that minor players would not be quite so starved of preferences as they would be under the JSCEM model.

This addresses a concern noted by Antony Green, that a very high rate of exhausted votes could result in the final seat being decided in a fairly arbitrary fashion — not to mention the irony that Xenophon’s own political career got rolling when he was elected to South Australia’s state upper house in 1997 with 2.9% of the vote and a heavy flow of compulsory preferences.

Leyonhjelm’s model, which carries the endorsement of veteran psephologist Malcolm Mackerras, would maintain the existing regime of numbering only a single box above the line, while greatly lightening the burden on below-the-line voters by allowing them number as few as six boxes.

However, Leyonhjelm’s plan crucially departs from the Xenophon and JSCEM proposals in that it maintains group voting tickets, so that above-the-line voters would continue to have a full suite of preferences determined for them by the party of their choice.

At the same time, it would dispense with the defining outrage of the current system, in which voters face a choice between surrendering their votes to preference negotiators and subjecting themselves to the gruelling task of rank ordering perhaps as many as 110 individual candidates (that being the record-breaking number of Senate candidates in New South Wales in 2013).

From Leyonhjelm’s perspective, the beauty of this proposal is the likelihood that voters would continue overwhelmingly to vote above the line.

This can be discerned from last year’s state election in Victoria, where a very similar system applies for the Legislative Council.

Despite all the publicity surrounding the state’s perverse Senate result the previous year, which delivered Ricky Muir of the Australian Motoring Enthusiasts Party a seat from just 0.5% of the vote, only 6.1% of voters made the effort to vote below the line, even though they needed to number only five boxes to do so.

The result was even more colourful than the Senate election, producing an upper house crossbench that includes two members from Shooters and Fishers, one each from the Australian Sex Party and the Democratic Labour Party, and another from a regional concern called Vote 1 Local Jobs, from vote shares ranging from 1.3% to 3.5%.

That the federal government now has the option of pursuing the Leyonhjelm model would appear to bode well for the future of group voting tickets, preference harvesting and micro-party senators.

Since Labor seems to have lost its appetite for more substantial reform, the government would need to enlist the support of the Greens to piece together a fairly unconvincing majority in favour of the JSCEM model or its Xenophon variant.

By contrast, the Leyonhjelm model has the potential to win over Labor and every crossbencher other than Xenophon and the Greens — and perhaps even them as well, since they could well conclude what was on offer to be at least marginally preferable to the status quo.