A referendum campaign is a cocktail. Emotional appeals, factual arguments, personality politics and plain old money all play their part in success or failure – the measures of each to add to the mix are decided by strategists and chance.

(Chance, by the way, should never be underestimated. The Scottish Yes campaign’s biggest donors are Colin and Chris Weir, who won £161 million on Euromillions in 2011. Had their numbers been picked by a unionist instead, it would be Better Together enjoying the £3.5 million bounty.)

Some arguments, such as that for Scottish independence, lend themselves to romance. Painting your face blue and impersonating Mel Gibson obviously has its limits as a tactic, though, hence Alex Salmond’s scramble for detailed economic arguments to leaven the Yes campaign’s offering.

On the opposite end of the scale, No2AV chose to make a primarily factual, financial pitch based on the cost of the electoral system – backed by a clever emotional appeal, reminding voters that almost no-one in the world used the Alternative Vote.

This week we saw the Better Together campaign launch their new slogan: “No, thanks”. I’m told this was inspired by the victorious No campaign in the 1995 Quebec referendum, which used “Non merci” as its slogan and saw the independence campaign narrowly defeated at the last moment.

It’s a sign of the unionist campaign moving to a more positive emotional approach. Given their message has so far been characterised by hard numbers and warnings of lost influence – “No” is of course an inherently negative word – it’s easy to see why they’ve chosen to let a little sunlight in.

What benefit can adding the word “thanks” really bring? In an age of popular scepticism about soundbites, focus groups and strategists, I’m sure many will scoff at the six extra letters. But it can have a powerful effect – consider the different dynamic between saying “No” and “No, thanks”. A simple bit of good manners turns an argument into a polite conversation.

As we all know, such politeness makes it very difficult for the person you’re talking to to be rude. It’s neutralising – the speaker is recognising the offer the other has made, but turning it down in a reasonable way.

This, I suspect, will cast the Yes campaign’s worst advocates into stark relief. The cybernats have become increasingly famous for their vitriol online – abusing those who disagree with them, denouncing No supporters are traitors, tarring their own cause with a poisonous torrent of bile. JK Rowling is their latest victim.

As the last few weeks of the campaign work themselves out, open-minded floating voters are being invited by Better Together to judge which company they would rather keep – cybernats, or the polite rejection of “No thanks.”

The cybernats are extreme examples, but the neutralising effect of that “thanks” strikes at the approach taken by Salmond himself. The First Minister has done his best to make people feel uncomfortable voting against independence. His language is that of voting for your homeland, of confidence in your nation, of pride in your identity – by implication, going against him is to vote against those things.

Some voters already feel a reluctance to confess their intention to vote “No” in September – an atmosphere in which you suffer disapproval or even attacks for expressing unionist sentiment can prove oppressive. It’s meant to be; delegitimising opponents by questioning their loyalty, their nationality and their morality is an age-old tactic.

It is Better Together’s intention to counter that discomfort, to reassure voters that it’s OK to turn Salmond down. They’re seeking to give the undecided a valid, comforting way to express that they have weighed the proposal, considered the evidence, and have decided not to take it up. “No, thanks” is their way to do it. No fighting, no shouting, but rather a gentle response to a sharp question. It might just work.