It’s the issue you just can’t get away from. Greens and preferences are in the news again, this time with an announcement yesterday from the Victorian Liberal Party that it will preference against the Greens across the board at this month’s state election.

Last week it was Labor’s turn to shaft the Greens, not actually preferencing against them but leaving open that possibility by rejecting a comprehensive preference deal. Daniel Scoullar in Crikey said that “If Labor receives Greens support and does not return the favour then it will be a clear case of petty party ideology over principles and policy.”

I’ve written about this a fair bit before, especially around the last Victorian election (see herehere and here for examples). Basically my view is that Labor needs to grow up and stop obsessing about the Greens, because its focus on the inner city is costing it votes in the suburban marginals where it needs them.

Conversely, the issue is a winner for the Liberals pretty much however they play it. Because their seats are mostly not under threat from the Greens they can indulge in the politics of symbolism and enjoy themselves exposing Labor’s incoherence.

But what’s most striking about this debate is its insularity. The rise of the Greens is a worldwide phenomenon, but you’d never guess that from listening to the ALP. At most there’s an occasional nod to interstate experience — Labor’s perception of “overseas” seems to stop at Tasmania.

In Europe, social democratic parties have mostly learned to treat the Greens as allies. That doesn’t mean agreeing with them about everything, or not trying to win seats from them, but it means not worrying so much about your Left flank that you lose sight of the main game.

Germany’s Social Democrats governed in coalition with the Greens for seven years from 1998, and have done so several times at state level. Similar coalitions (often with centrist parties as well) have held office in Belgium, Luxembourg and most of Scandinavia.

Australian politicians might dismiss this record as being solely a result of proportional representation, but that would be at best a half truth. Green experience in government extends to France, whose electoral system is very similar to Australia’s; there the governing Socialists have conceded several seats to the Greens over a number of elections in return for support in parliament, although the Greens’ two ministers walked out of François Hollande’s government earlier this year due to policy disagreements.

And it’s not just the ALP that could do with learning some European lessons. A look at overseas experience also calls into question some of the Greens’ tactics.

Victoria’s Greens seem set on pursuing alliance with the ALP — despite its resistance — to the exclusion of other options. But European Green parties have held the door open to co-operation with the centre-Right. Sometimes they have gone through it: Austria’s Greens have entered conservative-led coalitions at state level, and the Greens supported centre-Right governments in Ireland and the Czech Republic.

Obviously, a party that wants to be seen as progressive has to use this tactic sparingly. But ruling it out from the start just means that the party will be taken for granted. Unless it can credibly threaten to switch sides, neither the Liberals nor the ALP have any incentive to offer it anything much.

That’s the problem the New Zealand Greens had the last time Labour won government there, in 2005. Having painted themselves as Labour’s loyal ally, they were unable to join in the bidding war that resulted from a hung Parliament and found that Labour stitched up a majority without them.

But the rest of the world seems like a closed book to Australia’s politicians — to their own cost.