there was a time when the SNP fought Westminster elections on a simple if hopelessly unrealistic prospectus: “Give the SNP a majority of Scottish seats and we’ll start negotiating independence”.
The question of a referendum did not arise – winning more than half the seats would have been a mandate.
In just over a week, if the polls are right, the SNP will win half the seats in Scotland and more. But Nicola Sturgeon will not be demanding talks about a split.
She has made clear this election is not about independence and insisted she will not use a victory to press for another referendum.
Instead, she wants to use the leverage provided by a large block of SNP MPs to secure concessions from a minority Labour government. She says the SNP’s number one priority is ending austerity and has pledged to work with others for “progressive policies” across the UK, arguing – logically – that as long as Scotland remains in the Union, it is in Scotland’s interests to have good policies coming from Westminster.
Opponents are right, however, to point out that the SNP’s raison d’etre is still independence and UK politicians would be foolish to lose sight of that in their dealings with the Nationalists over the next five years.
But the SNP has shown it is more sophisticated than to rush into things. After it won power at Holyrood, the party set about proving it could govern effectively and implement policies before then trying to persuade voters to back independence. It was not part of the SNP’s original game plan to become a major player at Westminster, but if it does indeed find itself holding the balance of power, it may well be Ms Sturgeon and her colleagues will want to demonstrate again that they are responsible politicians committed to positive policies.
They will only want to hold another referendum when they can be confident of winning it. And despite the apparent enthusiasm at the moment, there are still lots of people the SNP needs to convince on a range of issues which made them hesitate over a Yes vote last time – from the currency to pensions to falling oil prices.
Exercising influence at UK level through an unprecedented block of SNP MPs would give the party a new focus and a high UK-wide profile.
But exactly how much the Nationalists will be able to achieve is not clear.
Despite Labour’s ruling out of any deals with the SNP, if the arithmetic dictates it there will inevitably be discussions.
But will it mean Ed Miliband dancing to Ms Sturgeon’s tune? Since she has pledged her party would not put the Tories into power, she would have little bargaining power over Labour if it came to the crunch.
And the manifestos show there are many things on which the two parties are more or less agreed – the 50p top tax rate, raising the minimum wage and abolishing food banks.
On spending cuts, the Institute of Fiscal Studies says Labour and SNP plans are closer than they like to admit. And on the biggest point of contention – Trident – the Conservatives would always back Labour plans for renewal, leaving the SNP protesting on the sidelines.
And what would the SNP be able to do if it turns out the Tories are able to muster enough support to form a government after May 7?
Ms Sturgeon and her party look on course for a dramatic success next week. It will give them unprecedented numbers at Westminster. But it is far from clear just how much power and influence that will ultimately amount to.