Illustration: Rocco Fazzari

Illustration: Rocco Fazzari

Three men wobble slowly along, single file, on bicycles, the only traffic on a minor road in a Brisbane industrial estate. The police had warned them not to create a public nuisance. There is hardly a soul visible other than the cyclists and a wary plainclothes policeman. Can you pose a public nuisance without a public?

As these forlorn figures pedal back and forth in front of a single-storey office building like lost tourists, the threat they pose is evident but unimpressive - mounted on wheeled carts they tow behind them are metre-high placards displaying the smiling face of the Greens candidate in today's byelection for Kevin Rudd's former seat of Griffith, Geoff Ebbs.

The audience they crave is inside the building, just out of reach. A knot of reporters and cameras is clustered around Tony Abbott and his candidate, the noted ophthalmologist Bill Glasson, as they feign interest in the Breezway windows at the back of the building on the second-last day of the campaign.

One cameraman, satisfied he has enough footage of Abbott in a high-vis vest, wanders outside and briefly turns his camera on the pathetic little parade of cyclists for want of other activity. The attention excites the three Greens, who try to wave without losing their balance: "Vote Green in '14," one shouts. The cameraman loses interest and goes back inside.

Frustrated, the Greens try to ride into the driveway to get closer to the media. After a few metres they find a member of the prime ministerial protective detail standing before them. They waver to an uncertain halt. A placard falls off a bike. Their leader, a diminutive grey-haired man wearing a red bike helmet and a tie with ducks on it, looks a lot like the candidate on the poster. The copper waves them off. They turn meekly and pedal off again.

A few minutes later the media pack drives off to a Westfield mall to watch Bill Shorten with his candidate for Griffith, employment lawyer Terri Butler, in another of the tired rituals of democratic politics, the shopping centre "walk-through". The Greens' effort at national exposure is rewarded with a couple of seconds of footage at the end of some of the channels' news reports that evening.

Nothing in the scene outside the Breezway factory hints at the fact that the man with the duck tie will be the decisive factor in today's byelection. Does it matter? Abbott has a large majority in the House. One seat more or less would make no difference to the arithmetic of power. He is assured of holding government.

And this is guaranteed - whichever party loses today will tell us wearily that of course it doesn't matter a jot. The winner, naturally, will tell us why it matters a great deal.

In truth, byelections do matter because they are a real electoral test of a government's standing during its term when, otherwise, opinion polls are the only index of its standing with the people.

Griffith, in southern Brisbane, was won by Kevin Rudd at the September 7 election. He survived a strong challenge from Glasson and a 5 per cent swing, cutting his margin from 8 per cent to 3. After losing power, Rudd retired from Parliament on the second day it resumed under an Abbott prime ministership. So it's Labor's seat to lose.

In fact, it will be a serious jolt to Labor if it loses because not only does it hold the seat, it should also benefit from the customary reflex of voters at byelections to vent frustrations against a sitting government. This anti-government swing has averaged 4 per cent in the 146 byelections held since Federation in 1901, the Parliamentary Library found.

So, on the face of it, Labor's margin of 3 per cent plus the 4 per cent anti-incumbent swing gives it a pretty decent head start of 7 per cent.

And it would be a coup for Abbott if his candidate were to win. He would interpret it as a strong vote of confidence in his government. He needs to find one; the polls so far don't indicate much confidence in the Prime Minister or his government.

Glasson, a rangy, energetic man with a no-nonsense demeanour, certainly isn't relying on Abbott to win votes for him. Abbott's coat-tails are not long enough for a candidate in a marginal seat to ride into power. In fact, Glasson goes to great lengths to explain that this vote is not about Abbott. He's trying hard to head off a protest vote: "Whoever they vote for on Saturday, Tony Abbott will still be the Prime Minister and Bill Shorten will still be the Leader of the Opposition. This is about who you want to be your member for Griffith."

Going into election day, there's no clear sign that Labor is enjoying the head start it should. Each of the two main parties has a primary vote around the mid-40 per cent mark, much as they were at the September ballot.

This is where the Greens come in. After the Labor and Liberal National parties, the biggest share of the vote will go to the Greens. In September their man, Geoff Ebbs, won 10.2 per cent of the primary vote. Of the voters who chose the Greens, an overwhelming 87.5 per cent directed their second preference to Labor.

Glasson actually won more primary votes than Rudd, but the flow of Greens preferences so strongly favoured Rudd that he won overall. So, as Ebbs says now: "Greens voters will determine the outcome," depending on which party they bestow their second preference vote.

Clive Palmer, incidentally, decided not to field a candidate. Speaking from the regal surrounds of his dinosaur park, the large Queenslander pronounced that "we're not standing in Griffith because we're focusing on the Senate election in Western Australia", anticipating a rerun of that flawed vote.

More likely is that Palmer has decided discretion is the better part of valour in the face of another likely drubbing in Griffith. The discerning voters of Griffith gave Palmer's party a mere 2903 votes or just 3 per cent at the election last September. That was only one-third the size of Palmer's vote in Queensland overall.

Abbott's man, Bill Glasson, concurs that the Greens vote will determine the result today: "Geoff's exactly right. The Greens will decide who's the next member for Griffith." That's why Glasson is chasing their preference votes. "I say to people, 'who you put No.2 is really important'." He wants Greens voters to understand that the Greens cannot win the seat. Ebbs, publisher of a local paper and a confessed computer nerd, cannot be the new member for Griffith.

Glasson talks up solar power and the importance of planting more trees in an effort to capture Greens preferences, but the Abbott government has given him a tough sell on the Great Barrier Reef. The government's decision to allow the dredging and dumping at sea of 3 million cubic metres of seabed to accommodate a bigger coal shipping terminal at Abbot Point threatens to damage the Reef ecosystem.

Ebbs says that it's not only Greens voters who've noticed: "Conservative voters take my pamphlet on the Reef, they agree with me on it, they know I've been consistent on it."

His goal is to increase his primary vote by 15 per cent, its level at the 2010 election. If he succeeds, that will very likely seal a victory for Labor.

But the Liberal National Party has some advantages too. Foremost is Glasson himself. He's the ideal candidate. Abbott described him quite accurately as "a community doctor with a lifetime of public service under his belt, someone who has done an enormous amount of charity work in Australia, aid work abroad, someone who's served his country in uniform as well as served his country in hospitals large and small around this state and overseas."

And in a profile on Glasson last year, the Brisbane Courier-Mail's Susan Johnson wrote: "Try as I might, I couldn't dig up anyone with a single negative thing to say about him. Everybody's mum was one of his patients, or everyone knows someone who was. Everyone knows about his volunteer work in indigenous communities and in East Timor. Everyone likes Bill Glasson."

Labor's Terri Butler is also a good candidate, a smart and articulate local with a history of helping workers wronged by their employers, but she can't compete with Glasson's 100 per cent local recognition.

The Coalition can probably count on voter turnout, too. Griffith electors have been called to the polls five times in two years for local, state and federal elections and many might decide they have better things to do on a Saturday. Some recent byelections have had turnout of less than 70 per cent. Labor voters are younger and less inclined to vote in byelections; conservative voters generally are more motivated.

For some of the people Rudd described as "the good burghers of Griffith'', the election is just a public nuisance. But it looms large for psychological and symbolic advantage in the political system.

Labor should hold the seat and Shorten's leadership will come under question if it can't. Abbott craves it. Glasson came within 1500 votes of winning in September. "If I can win, I'll be over the moon," he says. So will Abbott.