You’ve seen it posted on office walls and Instagram feeds: diamonds are formed under pressure. Well, so are career-ending mistakes. Hopefully Humza Yousaf, who last week collapsed his own government’s majority by ending the SNP’s cooperation agreement with the Scottish Greens and then resigned before a probable no-confidence vote at Holyrood, can find clarity and respite after what must have been a personally horrible year. Politics is unforgiving at the best of times, but it must not be forgotten that for a sizeable chunk of his time in office some of Yousaf’s family members were trapped in Gaza. He spoke honestly about the emotional toll, and became one of the few western leaders – out of clear principle, not just personal investment – to openly criticise Israel’s relentless assault on the Palestinian people. Yousaf claims to have joined the SNP out of sympathy with its opposition to the Iraq war. He was the party’s first millennial leader, from a left-leaning generation forged in the shadow of New Labour, Iraq and the financial crisis. When he became first minister in March 2023, it seemed to consolidate a modest left turn for the SNP. Two years earlier, Nicola Sturgeon had celebrated her party’s fourth consecutive Holyrood victory by bringing the Scottish Greens into government. The Bute House agreement (BHA) secured her majority, avoiding the legislative battles that plagued the SNP’s minority administrations after 2007 and 2016. As a “cooperation agreement” rather than a coalition, it agreed a shared policy programme and two Green ministers, but excluded certain issues. These reservations were designed to protect the SNP’s reputation as much as Green principles, which nevertheless became the subject of controversy. The Greens do not support the pursuit of GDP growth or fossil fuel extraction; the corporate lobby was appalled that such people were anywhere near power. Areas that were included in the agreement also prompted plenty of opposition, from gender recognition reforms to highly protected marine areas (HPMAs) and the creation of a deposit return scheme for glass bottles. The most damaging attacks, however, came from the UK government, which used its “reserved” constitutional powers to refuse an independence referendum and overrule legislation on gender recognition and the deposit return scheme, with support from powerful sections of Scottish civil society. The result was that the Greens had little to show for their time in office. It also meant that Yousaf could not take the reins of the SNP with much hope for his agenda. When the BHA was negotiated, both sides emphasised the importance of trust, with inbuilt arrangements to underpin mutual communication and respect. What they talked less about was the importance of confidence: chiefly Nicola Sturgeon’s belief that her popularity was enough to ride out the inevitable criticism of Green priorities. Sturgeon’s resignation, and the eruption of a police investigation into the SNP’s finances, tipped the SNP into crisis. Yousaf won a close leadership race against Kate Forbes, a devoutly religious conservative who sought to abandon the Greens and pivot towards business, and began his tenure with little support beyond nervous progressive activists in the SNP. In office, Yousaf did very little to consolidate any kind of vision or identity for his leadership. Burdened with disastrous public finances, he made this worse by announcing a populist council tax freeze in October 2023. This intensified pressure on Scotland’s embattled local authorities, but it also enraged the Greens, whose councillors are internally powerful. If Yousaf was seeking to emphasise his independence, he lacked the conviction or support to pull it off. The Greens, on the other hand, do not lack conviction. When, in the wake of further disappointments over carbon emission targets and transgender healthcare, their members secured an extraordinary general meeting to discuss the future of the cooperation agreement, Yousaf confused decisiveness for confidence and terminated the whole thing. Having tolerated both internal dissent and vicious external criticism for their role in government, the Greens’ reaction should have been predictable, and they duly indicated their determination to bring him down in a confidence vote. If Yousaf expected anything else, it was naive. He needed the Greens more than they needed him. He was protecting a huge electoral coalition; they are building from a low base of about 8% of the vote. If Yousaf is replaced by Forbes, the Greens are an obvious alternative for SNP supporters who cannot bear her views. If he is replaced by someone like John Swinney who can still work with the Greens, they will be able to trade their support for legislation on a case-by-case basis, without the compromises that came with a wider agreement and threatened party unity. Yousaf’s demise was astoundingly clumsy and unnecessary, and such a pointless calamity rightly disqualifies him from office. But such errors are not made in a vacuum. While much of the media focus on the Scottish dynamics of his failure, it is also the result of a new and profound change in the politics of devolution: the UK government, overwhelmingly elected in England, actively enforcing the limits of Holyrood’s power hand in hand with the Scottish government’s domestic opponents. Without those unchallengeable interventions from above to confound Scotland’s politics, there is a good chance Yousaf would still be in office. This is not something that supporters of self-determination should celebrate. Rory Scothorne is a historian and writer based in Edinburgh