Janan Ganesh comments on the surge in SNP support since the September referendum in Scotland:

Once we understand this, the SNP’s recent boom makes more sense. Scots are rewarding a party whose cause they essentially admire and punishing the parties who thwarted it — even if they themselves ended up siding with the latter in September. Factor in Labour’s slow decline in large parts of Scotland, Nicola Sturgeon’s freshness as SNP leader and Westminster’s slowness in devolving more power to Edinburgh, and the great mystery of SNP success is not so mysterious.

The unionist predicament since the referendum is that they won the vote mostly by ceding almost everything to the other side. Now they either have to follow through on the promises of greater devolution made during the campaign or stand accused of trying to con the voters. Either way, the constitutional question isn’t going to be “settled” as long as Scotland remains part of the union, and soon enough keeping Scotland in the union may appear to be more trouble than it is worth. The rest of the country may soon start wishing that ‘Yes’ had won so that the issue could start to be laid to rest. As it is, it will remain a live issue for the foreseeable future, and the SNP has every incentive to keep it alive.

The core of the unionist campaign was that independence was impractical, but unionists never persuaded most Scots that it was undesirable. Scottish voters were told that staying in the union would get them more of what they wanted at a lower cost, and now that is being shown to be much more debatable and uncertain than it seemed a few months ago. Unionists gave the impression that they were offering voters the best of both worlds when they were not really in any position to make that offer. As Ganesh explains, following through on the promises of more devolution increases the existing constitutional imbalances in the U.K. Meanwhile, whatever the unionists are prepared to offer will always be dismissed by the nationalists as less than what most people in Scotland want, and the nationalists will have a point.

If the U.K. government gives more powers to Edinburgh, that will eventually lead to the union’s unraveling, and if they refuse to do so they will all but guarantee another referendum in the next few years that is much more likely to produce a ‘yes’ result. Most unionists did not appreciate that winning the referendum by 10 points was not a landslide in the way that it might have been in another sort of election. They saw the outcome as proof that their side had trounced the nationalists, but that’s because they assumed wrongly that the referendum represented the conclusion of the debate instead of being just one stage in it. The union survived the vote in September, but it probably did so only by delaying dissolution for a few more years.