It was a bleak, wet winter’s day for the launch of the Greens’ national campaign yesterday at what Canberra is proud to call its ‘National Convention Centre’.

The centre boasts a ‘Royal Theatre’, a ‘ballroom’ and an ‘exhibition hall’, but the Greens had instead booked the rather smaller ‘Menzies Theatrette’, into which a couple of hundred Greens supporters tried to squeeze, unsuccessfully. MC was ACT Greens candidate Lyn Hatfield Dodds; after the requisite Welcome to Country and a song by NT Senate candidate Warren H. Williams (a balladic Great Southern Land, the highlight of the event), Bob Brown — the Menzies of the Greens, I guess — was enthusiastically introduced to the mostly over-50 audience.

While key Reps candidates like Adam Bandt were there, it’s clear the Greens are focussing on the Senate. Both of its TV ads are aimed at encouraging voters to consider giving their upper house votes to the Greens. Brown is cannily playing up an idea, dismissed by most psephologists, the Coalition could regain control of the Senate. To strengthen his case, he can point to his own warnings before the 2004 elections about the same threat that were ignored by the media. Much of Brown’s speech was about the Greens’ role in the Senate, including a strong emphasis on their role in passage of the second stimulus package, which also features strongly in their ads.

The actual policies listed by Brown were limited. A universal dental scheme; scrapping ATM fees; flexible working hours for carers; taxing junk food ads; the Greens’ sublimely silly interest in high-speed rail. They want to spend $10 million on a year-long high speed rail study. Such a study could actually cost around $20,ooo — enough to pay for one public servant to go and pull files from the Australian Archives at Mitchell here in Canberra and summarise the last round of studies done in the 1990s on high-speed rail. These would include the famous consultants’ report instigated by Kate Carnell in which no matter how heroic the assumptions plugged into the modelling were, they couldn’t make a business case for it.

In the intervening decade and a bit, Australia’s population hasn’t quintupled, nor has our landmass mysteriously shrunk 75%, the sort of conditions that might start to make an inordinately expensive project like a VFT viable. And that’s before you get into the debate about whether it should be ‘outdated wheel-on-rail technology’ or ’21st century maglev technology’.

Still, the Greens are the only party committed to a market mechanism to deal with climate change and Australia’s long-term need to kick its carbon addiction. The standard of economic rationalism has been dropped by the major political parties. It hasn’t exactly been picked up and carried by the Greens, but they’re at least waving it around on one of Australia’s most important long-term economic problems.

Watching Brown before the adoring crowd of Greens faithful — he is no great public speaker, but they lap it up — it’s hard to avoid the impression the Greens could be a lot more than they are, but that they’re caught between being a grassroots minor party and a legitimate third force in Australian politics. During the afternoon, the Senate group tickets are released, making it clear that, like 2007, the Greens are unlikely to manage a quota in NSW. Nonetheless, the balance of power still beckons, with challenges as well as opportunities. Many of the faithful in the Menzies Theatrette will be deeply unhappy if the Greens strike deals with an Abbott government in the Senate.

Questions also loom about the next generation of party leadership. Brown afterwards took a media question about whether he’d resign if the Greens vote didn’t increase, and lamented his critics were always trying to see him out of parliament. He’s right, but the question of ‘where to from here’ will be more important than ever for the Greens if they do as well as they hope on August 21.