This article appears as part of the Unspun: Scottish Politics newsletter.

It has been dubbed, by Andrew Learmonth of this very parish, the Bute House Disagreement.

First Minister Humza Yousaf declared this week that a vote for the Scottish Greens, his Scottish Government coalition partners, at the forthcoming general election would be “wasted” after they revealed they’d field 32 candidates for the poll.

That brought a stinging rebuke from Partick Harvie, Lorna Slater and co who accused the SNP of being “unwilling to step up when needed to protect our common future”.

On the one hand it’s hardly surprising that a political party would urge the electorate to vote for them and not others – they’d be pretty daft not to. Indeed, we’ve seen that even when it would be in the interest of the broader independence cause, the SNP did not urge votes for other pro-indy parties.

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Bute House disagreement: Greens tell voters to reject SNP at general election

At both the 2016 and the 2021 Holyrood elections, Nicola Sturgeon urged supporters to follow a #BothVotesSNP strategy despite the fact most of those second votes would be wasted. The electoral system at Holyrood, in which there is a first-past-the-post constituency vote and a proportional representation list vote, was adopted with the intention of making coalition the most likely form of governance.

Under the system, the more constituency seats a party wins, the more vote share it needs to have members elected on the list. When the SNP achieved so far the only majority in the history of devolution, the party lost 16 seats on the regional list. Four years later they failed to win a single seat in six out of eight regions despite having the highest vote share in each, and still followed a #BothVotesSNP strategy in 2021. Basically, no party is going to tell you to vote for another no matter the wider strategic goals.

The Herald: The SNP have ran a #BothVotesSNP campaign in recent Holyrood electionsThe SNP have ran a #BothVotesSNP campaign in recent Holyrood elections (Image: Newsquest)
Of course, the election expected later this year won’t be fought under the D’Hondt system but under a straight first-past-the-post one. In this it’s easy to see why Mr Yousaf has been so vocal in telling people not to vote for his coalition partners.

The First Minister has, correctly, pointed out that there is no chance of the Scottish Greens winning a seat at Westminster despite fielding 32 candidates. In 2019 they amassed 28,122 votes across the 22 constituencies they stood in, just over 1,000 per seat, and lost their deposit in every one.

Still, Nicola Sturgeon didn’t warn people off voting for them in 2019 and she wasn’t in government with Mr Harvie and Ms Slater. Her successor is, clearly, worried that votes for the Scottish Greens might be enough to lose his own party seats to Labour in some of the more marginal constituencies.

In 2019 Amy Callaghan beat Liberal Democrat Jo Swinson by 149 votes in East Dunbartonshire, with the Scottish Green candidate receiving more than 900 votes, while in Kirkcaldy and Cowdenbeath Neale Hanvey beat out the Labour candidate by 1,243 as Scott Rutherford took 1,628 votes for the Greens.

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Those marginal seats were against an SNP landslide, something even the most optimistic of polls aren’t predicting this time around. A resurgent Labour will be targeting a plethora of constituencies currently held by Mr Yousaf’s party and even in areas where they’re less of a threat there will be anxiety over potential vote splitting. In Caithness, Sutherland and Easter Ross, the Libs Dems held on by just 204 votes last time out – what chance of the SNP overturning that when the Scottish Greens will be standing this time around?

The whole snafu arguably points to the problem with first-past-the-post voting. The Conservatives currently hold 56.2% of Westminster seats despite receiving 43.6% of the vote. Labour are expected to receive a similar vote share at the forthcoming election but likely to gain even more seats, with the website Electoral Calculus putting them at a high of 536.

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Proponents argue that such a system produces more stable governance but, well, *gestures vaguely at the past decade*. Humza Yousaf is right that voting for the Scottish Greens in a Westminster election is, beyond sending a message, pointless.

That’s arguably a more damning indictment of the Westminster system than anything he or his party have managed to come up with in the last few years.