In TV broadcasts where the independence referendum is discussed it is not unusual to hear the interviewer suggest to a guest pundit or politician that the Yes campaign needs a game changer; what can they do? they implore.
The justification for such loaded questions is usually the opinion polls which indicate a significant gap between support for Yes and No.
As with all election campaigns, it is rarely the clever strategy that can give one side the edge over the other but the unexpected event, the happenstance. Just such an event happened today when the UK Treasury announced its intention to underwrite every penny of the UK's debt mountain which currently stands at 1.4 trillion pounds.
The Yes campaign didn't need a game-changer, the panic that has engulfed the No campaign since the turn of the year has been evident and growing for some time.
Polls have slowly started moving in the wrong direction as far as the No campaign are concerned as the public have grown impatient waiting for the fabled positive case for the Union. David Cameron has run a mile when asked to defend the Union in a straight debate with Alex Salmond.
But the Treasury announcement is a massive development in a debate that has lacked certainty.
Currency, like the EU, has been a port in a storm for the No campaign whenever the debate got a bit rough.
How many times have we heard a senior Unionist politician argue that there will be no currency agreement, no lender of last resort and nothing but the euro for a newly independent Scotland? Even on the day of the Treasury announcement, Danny Alexander was still claiming that a currency agreement between London and Edinburgh was highly unlikely.
There are several reasons for a currency union - one hundred and thirty billion of them to be precise. That's how much Scotland would take on in the event of a Yes vote … assuming of course a suitable post referendum agreement with London can be reached. It's more than Scotland's entire budget for four years - five if you factor in future Westminster cuts.
When Salmond said Scotland's hand had been strengthened with the announcement, he wasn't kidding. The amount of debt Brown, Darling and Osborne have run up is eye watering and under international law there is absolutely no requirement for an independent Scotland to pay one penny towards it.
The Treasury decision has brought into the open something the Scottish Government's Fiscal Commission said months ago, that all debt accrued by successive UK governments has been done so under the title of the UK Government.
This means that - even if both London and Edinburgh wanted to - the debt cannot be split in order to pass a proportion of it onto a newly independent Scotland. The debt, all of the debt, is the UKs and that cannot be carved up unless international bond holders agree to it, and they won't.
Even Downing Street admitted that they were now powerless to insist Scotland accepts part of the debt. Asked how they would compel a newly independent Scotland to take on some of the debt, a spokesman said:
"In the event of a Yes (vote), there would have to be bilateral negotiations involving the UK Government and the Scottish Government."
But the Scottish Government is not washing its hands of its obligations as far as servicing this debt is concerned. Alex Salmond has made it clear Scotland will shoulder a fair share of the burden.
The quid pro quo as far as the SNP is concerned is a currency agreement between Holyrood and Westminster. It's an eminently sensible negotiating position that actually serves both parties well.
Salmond always knew it, and now we know it, he has Westminster by the short and curlies. But this is not a game of pain, neither party has anything to gain from antagonising and hurting the other. It's why a currency agreement will happen.
A currency agreement sees the UK balance of payments benefit from hard collateral that is North Sea Oil, and the international money markets, whose prompting led to the Treasury making the announcement, take comfort in knowing that all of the UK debt will be serviced in pound sterling with no rancour. Money markets like consistency and predictability.
Another factor that make a currency union a no brainer includes the hundreds of millions of pounds of trade carried out by English based businesses with Scottish customers. Would a government in the rest of the UK deliberately create problems for its own people by introducing barriers out of spite?
Remember that post a Yes vote, the career driven Scots MPs and their bitterness will disappear from Scottish politics. Scottish and rUK civil servants will sit down and an amicable dissolution of the Union will be agreed.
The Treasury announcement is a sign of common sense and pragmatism. That it came on the same day that Alistair Carmichael launched his 'top-twenty' reasons to vote No, completely overshadowing it, shows it was not a co-ordinated attempt to help the No campaign.
Money talks and £130bn pounds can make a lot of persuasive noise, especially if the international money markets are listening.