The 20 per cent that doesn't is especially important in election results. If Labor got them all, the contest would be neck and neck. Green voters are not all Left/Labor in major party terms. That will surprise some Greens but it is a plus for the party, which needs to have some appeal across the political spectrum if it is to grow.

Another interesting fact is Bob Brown's rating among Australia's most powerful political leaders. In its recent Top 50 in Politics he was rated No 1 by The Australian newspaper's political writers. But he is too wise to be flattered by The Australian, which is offering him a poisoned chalice. Australians don't like a minor party leader to have too much power. It does Brown no good at all to be portrayed as Australia's most powerful politician. He is actually powerful enough to be about fifth or sixth, behind the two party leaders and two or three senior ministers, but no higher.

At the moment considerable attention is being given to the Greens' internal affairs. Former NSW Labor Premier, Bob Carr, says about time but really there has been a decade of full attention, back at least to the 2004 federal election. The most recent analysis, by Sally Neighbour, ''Divided we Fall'', is in the current issue of The Monthly.

She concentrates unduly on NSW, the Greens' troubled state, but addresses big questions. How, if at all, are the Greens different? Will the party survive longer than its minor party predecessors, the Democrats, One Nation and the Democratic Labor Party?

The story of some of the Greens' internal affairs is salutary for all who believe that the major parties are such an awful mess that it must be possible to do politics better. The Democrats had the same high aspirations but fell short because of extreme internecine conflict over leadership, representation and policy at both the federal and state levels. The Greens too, in some states, are a case study in the debilitating influence of personality conflicts and the battle for control within political parties. Self-interest seems to be hard-wired into human beings.

All parties contain extraordinarily diverse views. Think of the difference between Senator Corey Bernardi and Malcolm Turnbull in the Liberals, for instance. So it is no surprise to learn of deep differences among the NSW Greens or between Lee Rhiannon and Bob Brown. But the fabric of small parties is much more fragile and such differences can hurt a small party.

The Greens also exhibit extraordinarily different state configurations. Their state parties have different histories, rules, policy priorities, and ideological views. Once again you could tell a similar story for the major parties. But this sort of diversity is camouflaged in the bigger parties and potentially more damaging to a small party. The bigger parties have a wider range of public representatives and their eccentrics and nut-cases are regarded as just that: not representative of the party as a whole.

The Greens will survive long-term because of the bottom-up nature of the party. Neighbour notes this factor, including more than 100 Greens in local government, but doesn't quite get it right. Other minor parties, including the Democrats and One Nation, have been bottom up too, but in a different way. Remember the initial public meetings at which Pauline Hanson and Don Chipp drew huge crowds. Those parties grew too quickly and exploded on to the public arena. But the Greens have grown slowly and worked through local government in the way other minor parties never did. They will not go away.

This leaves two more questions. How will be the Greens perform at the next federal election? How will they cope with an Abbott-led Coalition government?

The Greens' steady support in the public opinion polls suggests party members will again be strong contenders for six Senate seats in a half Senate election. They may even poll a little more strongly than the 13 per cent for the Senate in 2010. More often than not they have polled slightly above that over the past 18 months. They may lose the seat of Melbourne but grow in the Senate.

The Greens will hold the balance of power again no matter who forms government after the next election. Almost certainly it will be the Coalition. The question of what they do then is the biggest one for the Greens. Some insiders will want to pretend the election result never happened and try to defeat the Coalition from the mountain tops of the Senate. That strategy would end in disaster because the Coalition would either govern by reaching an accommodation with Labor or call a double dissolution election and ultimately emerge victorious.

The better course is negotiation and parliamentary compromise.

Undoubtedly that would be difficult just as the Democrats found dealing with the Coalition harder than with Labor.

But they did it when they had to.

The Greens are ideologically further away from the Coalition than the Democrats were, of course, and less inclined so far to appreciate the art of compromise.

But they are learning that art and would continue to do so, perhaps with an acrimonious split or two along the way, during a Coalition government.

John Warhurst is an emeritus professor of political science at the Australian National University.

John.Warhurst@anu.edu.au