EVEN if you were to judge it by the mediocre standards of party political broadcasts, Thursday night’s offering by the SNP was insipid. The message was unsubtle and uncomplicated: The Westminster Parliament is old and decaying; Holyrood is young and vibrant and a place where progressive things happen. With opinion polls consistently suggesting that the SNP Government will be returned at Holyrood with a second overall majority following May’s election, perhaps the party feels it doesn’t need to tax its creative reserves too hard while sculpting a three-minute broadcast.

In any event, only one issue is concentrating the minds of Nicola Sturgeon and her chief strategists as the countdown to the Scottish election begins to gather speed and it won’t be featuring on the pre-election marketing any time soon: what to say about a second independence referendum in the party manifesto.

The First Minister is facing a dilemma and how she resolves it will resonate far beyond the outcome of the Scottish election. Does she boldly pledge to seek a second referendum buoyed by the optimistic expectations of her party’s new model army of 100,000 members? And, if not, does she include any significant reference to a second referendum at all?

A curious game of cat and mouse over this issue has been played out over the last couple of months. The Sunday Herald’s respected political editor Tom Gordon recently reported that there would be no commitment to a second independence referendum in the party’s election manifesto for Holyrood. An irked Ms Sturgeon immediately tweeted that this was news to her.

In speeches and interviews before and since she has sought to dampen expectations of a manifesto commitment by suggesting that a game-changer, such as Britain’s exit from the European Union against the wishes of a majority of Scots, would be required to trigger a demand for another referendum. After all, say those who favour a long-term approach, she would only seek a second independence vote if she could be certain of victory. Yet it seems implausible that she will ever experience such certainty.

The waves of support for the SNP following the first referendum nearly 18 months ago came cascading in on the expectation that independence was now well within grasp and that, in Ms Sturgeon, the movement had a leader who could make the dream come true. If the First Minister is to kick a referendum pledge beyond the scope of the next parliament there will be more than a degree of disillusionment among many of her party’s newest supporters. Okay, so support for the SNP does not necessarily entail support for Scottish independence, else the outcome of September 2014 would have been a different one. But it’s fair to assume that you don’t register to become a member of a party with independence as its core belief unless you also want independence.

It’s also fair to assume that the emotion, fervour and euphoria of the first referendum campaign which sparked the 100,000 membership surge yet rages in their souls. How many want a second independence referendum as promptly as possible and to what extent will their initial fervour wane if they are told they must wait until around the middle of the next decade before they have a chance to unfurl the Yes banners? This is what Ms Sturgeon must weigh up before the election manifesto finally appears in around two months’ time.

If there is not to be a firm manifesto commitment to another referendum how many will want to know why their views on the matter were not taken into account? Many will feel that the game-changer of Brexit against the wishes of Scotland will probably never occur. And anyway, it’s not as if there haven’t there been other "game-changers" to stiffen the resolve to decouple from the United Kingdom. Austerity, the death of British steel and the proposed Victorian trade union legislation are all, despite soaring talk of handing government back to the people, evidence that the pattern of top-down politics by rules drawn up centuries ago, will always prevail. English Votes for English Laws and the final exposition of the Smith Commission as a hastily-assembled political decompression chamber have added to the sense that Scotland remains a branch office.

Who knows where the world will be in the mid-2020s and on what geopolitical currents it will have travelled to that place. We are witnessing the approaching menace of the White House becoming the global headquarters of Donald Trump and so-called Islamic State bringing their dirty war to the ramparts of so-called civilised Europe. And what price will this continent one day be made to pay for walking by on the other side as an ancient civilisation in the Middle East was being wiped out? In the midst of such earth-moving events one small nation’s struggle for self-determination, where no-one’s life is at stake, may soon lose its power to engage. If Scotland is to meet this shifting of civilisations as master of its own destiny rather than merely as holder of the jaickets then time may already be running away; the tide that has brought us to the edge of independence may soon be preparing to turn again. So better, perhaps, to have tried meaningfully one more time and soon than to see that opportunity disappear in the smoke of other people’s bigger battles.

Yet, even though Ms Sturgeon will never arrive at certainty over the outcome of a second referendum, she wants to give herself the best possible chance of triumph, knowing that there won’t be a third one in her lifetime. By the end of the next Scottish Parliament’s lifespan its citizens will have participated in six national polls in the space of six years, including the EU referendum, European Parliament and local council elections. If the First Minister were to add an independence referendum within that timeframe she risks exposing the voters to election fatigue. Nor can she enter a second referendum campaign without a viable fiscal framework that doesn’t rely on sterling and which must probably include plans for a Scottish clearing bank. Each of these would have to be in the process of being prepared now if they are to be ready in less than four years.

A commitment to an independence vote has appeared on every SNP manifesto since the birth of devolution in 1999. Only on this one, though, does it possess the power to fulfil or shatter the dream?