On Saturday 27 November Victorians will go to the polls to elect the next state government.

Ordinarily, state and federal elections are contests between the Labor party and the Liberal-National coalition.

The single member district electoral system used for Victorian lower house elections means that the contest is usually between the two big parties, with minor parties confined to the role of preference wheelers and dealers in a handful of crucial marginal seats.

Consistent with this, Labor and the coalition will be slugging it out in the upcoming election, although the battle between the major parties represents just one campaign that will be waged in the 2010 contest. A second, no less robust battle will be going on in the inner suburbs of Melbourne and it involves the Labor party and the Greens.

The rise of the Greens has been a dramatic development in Victorian politics. When Labor narrowly won the 1999 election, there were 20 Green candidates contesting the 88 available seats, and, of these, the only inner urban division to see a Green candidate was the old seat of Coburg (now Brunswick).

This candidate polled a mere 8 percent. By 2002, however, Greens candidates were contesting all divisions, with the candidate in Brunswick polling 24.3 percent.

By 2006, the Green vote in Brunswick was 29.7 percent.

The Greens are now tipped to win this seat, and the lower house seats of Melbourne, Richmond and possibly Northcote at the next election!

On the basis of recent opinion polling, some suggest that the seats of Prahran and Albert Park might also be winnable for the Greens.

Were all six seats to go the Greens, and were the Liberals to pick up a few marginal government seats, the Greens would probably end up holding the balance of power in a ‘hung’ lower house.

This is probably a worse-case scenario for the Labor government, but, as the federal election showed, an equal outcome is by no means beyond the realm of the possible. Were the Greens to hold the balance of power, the most likely outcome would be some form of parliamentary alliance with Labor.

Still, premier Brumby would rather be in a position where he could govern in his own right, so the Labor party has to concentrate its campaign effort on those inner city seats to try to contain the Green tide.

This is in addition to having to defend Labor seats in the outer suburbs of Melbourne and across the state’s regional cities.

The Greens have also caused Liberal leader Ted Baillieu a bit of grief. Despite the impression being formed by the polls, the Greens are still a long way from being able to win lower house seats without the help of preferences from the Liberal party.

This has been a bit of a problem for the opposition leader, who reasons that, if the Liberals are going to help the Greens in Melbourne and Brunswick, the Greens might like to help the Liberals in marginal seats like Burwood and Mt Waverley.

The idea of a preference deal between the Liberals and the Greens makes strategic sense, but the prospect of such a left-right alliance has caused apoplexy amongst some of the more conservative members of Mr Baillieu’s party, including former prime minister John Howard and senator and former state party president Helen Kroger.

Both went public urging Baillieu not to do a preference deal with the Greens.

In so doing, they exposed Baillieu to the impression that he leads a party divided on a core issue in to the campaign. What were they thinking?

Dr Nick Economou is a senior lecturer in Politics at Monash University.