There are plenty of ways of telling someone you’re a member of the Scottish Green party without telling them outright. You could lean on the old cliches, for instance, and display your preference for “open-toed sandals, beards, long hair and exotic, brightly coloured garments” – that’s how Robin Harper, the party’s first ever MSP, lamented the traditional public image of Greens in his autobiography. Or you could update the stereotype for the 21st century and list your various higher education qualifications: whether apocryphal or not, it’s generally assumed that the Scottish Greens have the most doctorates per member of any party in Scotland. But to bring things fully up to date, you could simply announce that you’re one of the most powerful people in the country. At the end of this month, a special meeting of Scottish Green members will determine whether or not to sign a governing deal with the SNP, the details of which should emerge by the end of this week. May’s election produced a delicate balance of power at Holyrood, handing the SNP 64 MSPs – just one short of a majority. Between them, the opposition parties have the same number. The Greens’ contingent, initially expanded from six, was reduced from eight to seven after their MSP Alison Johnstone broke ranks and ended a bizarre parliamentary standoff to fill the unwanted non-partisan chair of presiding officer. Since 2016, Green political power has derived from their ability to side (or threaten to side) with Labour, the Conservatives and the Liberal Democrats – the unionist parties – against an SNP minority. While there is not much common ground between all four, this still created some instances of genuine parliamentary independence from the executive, such as repealing the Offensive Behaviour at Football Act and several symbolic government defeats. More importantly, it provided vital negotiating power. But the election result, combined with Johnstone’s removal from the fray, has subtly but significantly changed the balance. When Holyrood is evenly divided on an issue, convention dictates that the presiding officer gives the casting vote to the status quo. Assuming Nicola Sturgeon can whip her MSPs behind the government, the opposition parties have lost their ability to pursue an independent agenda – all that is left is the power to block change. Without a deal, stalemate beckons. This means that despite gaining seats in the election, the Greens risk losing some of the influence that came from flitting between government and opposition to shape the agenda. Party insiders frequently point to focus groups conducted in the run-up to the election, which found that voters warmed to them when they could identify tangible policy achievements to match popular principles. While another term in opposition risks a crisis of relevance, a deal could secure a clear policy legacy to campaign on next time round. For the SNP, the appeal of a deal goes beyond stable government. Cop26 will soon take place in Glasgow, and Sturgeon hopes to helm a formally Green-tinged government under the global glare, burnishing Scotland’s credentials as a “world leader” and deepening the contrast with the UK government. That is related, of course, to Sturgeon’s famously fragile “mandate” for an independence referendum, which relies on counting on Green MSPs as well as SNP ones. Formalising this arithmetic helps to strengthen Sturgeon’s claim that the will of the people, refracted through Holyrood, is being denied. The nature of the deal is already being advertised as something new, perhaps even “radical”, with the Greens potentially claiming one or two ministerial roles without having to agree on a full programme for government – leaving them free to disagree in various areas. This is being called the “New Zealand model” thanks to a similar deal forged by Labour’s Jacinda Ardern with the New Zealand Greens. Ardern is a kind of antipodean Sturgeon, moderate and popular, and both have sought to portray themselves as defenders of the same open-society values that Greens have made their own elsewhere in the world. Yet the novelty can be overstated. The SNP dealt with the Greens in 2007, as well, albeit in a far more limited deal than present proposals. When that deal expired, after the SNP’s first budget, the Greens tried to throw their weight around. In their second budget, the SNP rebuffed Green demands to fund an ambitious home insulation scheme, and when the Greens pulled their support at the last minute, Alex Salmond pivoted towards the other opposition parties. Several things have changed since then to make a more durable deal possible. Sturgeon is not Salmond, for a start. She is not boorish, her Machiavellian tendencies are better-concealed, and she shares with the Greens a commitment to progressive cultural values – especially on trans rights and the reform of gender recognition law – that have become controversial within the wider nationalist movement. The prominence of that wider movement reflects another crucial change, for the constitutional question has soared in importance since 2007, reorganising Scottish politics around Yes and No to independence. Independence was sufficiently low down on Scottish Green priorities in 2007 that Harper himself could quietly oppose it without controversy. In contrast, the party’s current co-leaders, Patrick Harvie and Lorna Slater, are two of Scotland’s most prominent advocates for the cause. But it’s not just the SNP’s raison d’etre that has moved up the agenda. The climate crisis will define the next decade like never before. Yet if Sturgeon is hoping to use the Greens to camouflage her party’s exposed flank on this question, she is taking a big risk. The fact that Green members will decide on the final deal is an indication that the party takes the integrity of its agenda seriously and giving them space to continue disagreeing with the government – as the deal reportedly will – is a strange form of cover. There is another side to the Greens’ ideological commitment that could pose problems. They are a small party for a reason. Much of their agenda goes beyond what the general public is comfortable with, and Sturgeon’s opponents and even some allies – inside and outside her party – are already presenting them as a dangerous, extremist influence on her government. The SNP has secured its predominance by acting as if it comfortably manifests the passive will and identity of the Scottish people, flaws and all. What will happen when they are so clearly attached to another, more active set of political interests? For the same reasons, the Greens will soon come under an unprecedented amount of scrutiny. Their delicate, carefully balanced structures of internal accountability and deliberation may struggle to carry the new weight. In 1988, Donald Dewar argued for cross-party collaboration to secure a Scottish parliament, proclaiming that “the people must decide if they are prepared to live a little dangerously to achieve what they want”. But devolution was the safe option. With independence and climate change, there are few safe options, and with this deal the SNP and the Greens are both living dangerously. In a country so deeply polarised between Yes and No, and a world torn between climate radicalism and political caution, it won’t be so easy to give the people what they want. Rory Scothorne is completing a PhD on the radical left and Scottish nationalism between 1968 and 1992