Two decades after devolution, the Scottish Parliament’s election system still confuses ordinary voters and seasoned political observers alike. Politicians on both the Unionist and Nationalist sides have capitalised on this complexity, putting forward new parties – most prominently George Galloway’s Alliance for Unity (A4U) and Alex Salmond’s Alba – that aim to game the system and maximise their side’s (on the matter of the constitution) number of MSPs by pulling regional list votes away from the major parties.
But in fact, beneath its byzantine name and workings, Scotland’s modified d’Hondt Additional Member Electoral System translates to straightforward arithmetic, with a clear and inescapable conclusion: Galloway’s A4U gambit is likely to backfire, doing real damage to the Unionist cause. On the other hand, the mathematical structure of Scottish elections means that Alba is much better positioned to succeed, and has the potential to artificially inflate the Nationalist share of MSPs.
The main reason that these parallel ventures have such divergent chances of success is that most Nationalist MSPs are elected with constituency votes, while most Unionist MSPs are elected from list votes. Put simply, this means that the potential upside of manipulating how list votes are allocated is much higher for Nationalists than for Unionists, and the corresponding risks are much lower.
But to understand the situation more deeply, we need a brief detour into how Scottish elections actually work. On 6 May, each Scottish voter will be assigned two votes: a constituency vote and a regional list vote. 73 out of Holyrood’s 129 seats are allocated using the constituency vote, which works along the same lines as the first-past-the-post system used in UK-wide general elections – whichever party wins the most votes in each constituency gains an MSP for that constituency.
Historically, the SNP has virtually swept the board of constituency seats. In 2016, the SNP won 59 out of 73 constituency seats, providing close to the entirety of their Holyrood delegation.