I’ve made this point before, but I’m constantly reading articles about the rising share of “protest” votes going to “minor parties” in which the set of minor parties excludes the National Party. The reason is, of course, that the Nationals are a long-established party which, with a few state-level exceptions, operates in permanent coalition with the Liberals.
But, for all practical purposes, the same is true of the Greens. Roughly speaking, Labor and the Greens are in the position the Liberals and Nationals (and previously the Country Party) were for most of the 20th century. They fight three-cornered contests, often bitterly, and do a lot of agonising about preference swaps, coalitions and so on. But, when push comes to shove in terms of forming governments, they almost always line up together, whether in a coalition, with a formal agreement, or with informal support.
The most important difference between the two is that the Greens get more votes from a wider range of electorates. The difference that drives the spurious analysis of “protest parties” is that the coalition between Labor and the Greens is less formal and more fractious than that between the Liberals and Nationals.
If you count Labor and the Greens as a coalition, then the rise of protest parties in Australia appears primarily as a crackup of the political right. We’ve seen a profusion of rightwing protest parties, with only
the Xenophon group in the centre, and nothing much at all on the left. That differs from the situation in some other countries, where social democratic parties have embraced austerity and collapsed (Greece, Netherlands) or where the established leadership has been pushed aside (UK and possibly soon US also). I have some ideas about this, but I’ll have to write about them later.
But, coming back to the main point, a consistent analysis should treat both the Nationals and Greens as minor parties, or else neither of them.