With thanks to Sam Mace, Labour Party member, for his excellent knowledge of Labour and electoral politics.

The unexpected rise of Jeremy Corbyn poses a dilemma for the Green Party. Whilst clearly agreeing with a lot of what he says and stands for, and welcoming the spicing up of a usually bland political discourse, only the naïve would fail to realise he presents a real electoral threat to us. We have, for some time now, painted ourselves as an alternative to a Labour that has lost its way- if Corbyn were elected, would such a caricature hold sway anymore? Politics is a complicated business, especially the multi-party one we find ourselves in now, and so there are positives and negatives for the Greens to consider whether the Islington MP wins or loses this leadership race.

Let’s take the case of Corbyn losing first. It could decisively seal Labour’s fate in the eyes of many, although by no means all, of the British Left and prompt many of those still hoping for a renewed socialist Labour to finally abandon the pipe dream and look for a new home. Many of these could settle with the Greens, but this shouldn’t be assumed. There seems to increasingly be the notion that the Lib Dems have been hard done by, and in some quarters people feel that they halted much of the worst of Tory policy and should be praised for this. Add in the newly elected left-wing Farron and the Lib Dems could scoop up a number of left-wing disaffected Labour members that could otherwise be going to the Greens: should Corbyn lose the Greens should not be complacent but rather see it as a signal to up their game. Maybe, however, Corbyn coming second will do enough to plug the exodus and leave us, depressingly, still debating whether there is any hope for Labour reverting to a left wing force or not, pretty much back to square one.

The flip side is that a Corbyn loss could also decisively seal the fate of left-wing ideals in British politics, at least for a while. Many commentators crow that the public definitively rejected socialism when they rejected Miliband: how much more so will they say this when even Labour party members don’t propel a genuine socialist agenda to victory? The other candidates are likely to fail to draw the lessons they should from the storm Corbyn has caused, instead continuing to crow that only a ‘balanced’ ‘business friendly’ approach can woo voters. This could make the Green voice become increasingly marginalised and obscure in a political rhetoric even more bland than we currently witness.

A Corbyn win, however, also comes with its own problems. It will make it harder, although not impossible, for the Greens to gain ground electorally, with the ‘only party of the Left’ line being harder to sell. It could open the doors to a progressive alliance and Labour backing off in key seats, however, so our share of seats may go up even if our share of the vote remains fairly unchanged. Corbyn may be open to this but there would, I suspect, be significant resistance within his party, particularly from those who would be required to sacrifice a chance at the Commons. There’ll likely be many more controversial issues higher up on Corbyn’s agenda if he won so he won’t want to use up too much of the good graces of his backbenchers on this issue.

Just as him losing may sully the name of the Left in the eyes of the public (aided by the tabloids no doubt), a Corbyn victory would surely begin to draw the Overton Window back towards the Left after years of a rightwards trajectory. It would mean many of the ideas of the Greens, currently scoffed at or ignored, might begin once more to be discussed in the mainstream and, heaven forbid, maybe even debated in the Commons. This could lend an air of legitimacy to the Greens, as well as see more and more people begin to seriously consider at least some of our policies.

It’s also important to bear in mind that even if Corbyn does win, Labour won’t be magically transformed overnight. He may well help make some left-wing proposals enter into the political rhetoric, but this may serve only to pave the way to Green success if he proves ultimately unable to bring his own party in line. Much of his promises, although undoubtedly heartfelt now, may simply be unable to get past the Blairites that will still dominant the higher echelons of his party. A Corbyn that fails to deliver (some have drawn analogies to Tsipras in Greece) or is deposed too soon, may end up pushing more people towards the Greens in the end anyway.

This brings us to the matter of a Labour split. If Corbyn loses it’s more likely there’ll be a considerable number of disgruntled Corbynites looking for a new home with the Greens or Lib Dems, but not a decisive split. If Corbyn wins, however, it seems more likely (although still far from certain) that they’ll be a real break-up, if not straight away then at least in the near future, as the unhappy ones in this instance are more likely to be senior party figures rather than grass roots (although many currently threatening a coup are probably not entirely genuine).

If there is a split, should the Greens consider an alliance with the more left-leaning of the pair? Or possibly even a formal merger? Such a move could reinvigorate both parties of the merger and become a really bold and energised movement of the broad left, something desperately needed if climate change and inequality are to be halted before they cause irreparable damage. The left-wing Labour splinter would hopefully bring strong links to trade unions and traditional working class strongholds in the North, whilst the Greens would bring a vision and understanding of how interconnected so many policy areas are, how economy impacts society which impacts environment, as well as better internal democracy and inclusion of minority groups. Many Greens, however, will feel that there would still be irreconcilable differences between even the left of Labour and themselves, perhaps distrusting people that supported a party so terrible in opposition, whilst many of the Labour splinter may question the electoral advantage to be gained from siding with the Greens.

All or none of the above may be right: political foretelling is a risky business at the best of times, and the past year has been some of the most unpredictable and tumultuous in recent history. I have always been struck by how many within the Green Party view their involvement in the party as about more than partisanship: they are in it for the values of the party, not purely electoral gain. If Corbyn doing well edges these values a little closer to realisation, then we should support him, in whatever way we feel comfortable with. The spotlight is on Left-Wing ideas now like it hasn’t been in some time: those that support such ideas should overcome the stereotype of a fractious and bickering Left and instead see this moment as an opportunity to do some good, Greens included.