With the "Better Together" side comfortably ahead for much of the summer, it had appeared that Scottish First Minister Alex Salmond's merry band of nationalists would be thwarted.
Now, last-minute concessions have been offered to the Scots, with the hope it will turn the tide before they vote to kiss England, Wales and Northern Ireland goodbye.
Political figures have headed north to say their piece, including the prime minister (David Cameron), the deputy prime minister (Nick Clegg), a former prime minister (Gordon Brown) and the aspiring prime minister (Ed Miliband). Even the charlatan (UKIP Leader Nigel Farage) has chipped in from the pub, telling Scots that a No to the U.K. is a big fat Yes to the cesspool of the European Union.
Will it be enough? We'll know Thursday, but right now it's too close to call.
There is no doubt Salmond has set a canny referendum table: he has a clear question with no devolution third option, he has excluded the 800,000 or so expatriate Scots from the ballot box but not patriotic new immigrants and he has lowered the voting age to 16 to encourage youth to vote.
Ah, youth. Impulsive, reckless youth. The potential Salmond master stroke. He proposed extending the franchise, and Cameron agreed. Was it wise?
You could place dozens of adjectives in front of "youth" before you came to "cautious" or "considered," which is what a decision on independence needs to be.
If you're cautious or considered as a young person, you're doing it wrong. Being young is about being carefree and impetuous, about living life your way and damning the consequences.
Which is precisely why Salmond was so eager to stick a ballot into their hands.
It makes sense. What young person doesn't feel hard done by, no matter how good they have it?
A week ago, the ploy appeared to be working, as the "shock" poll that put Salmond ahead showed that 57 per cent of people aged 16 to 24 supported independence. A subsequent poll has youth swinging the other way, so there clearly is volatility in that youth vote. How much of that volatility is in that 16-to-18-year-old cohort isn't clear, but we can presume there's some.
The whims of teenagers
This referendum is the ultimate opportunity for youth to stick it to the man, whom Salmond has deliberately named "David Cameron," instead of the more accurate "United Kingdom." Besides, what young person likes Conservatives, whose political appeal usually strengthens with age? Salmond has found the perfect foil.
Am I taking too dim a view of youth? Perhaps. Am I being patronizing? Maybe.
But there's a reason we don't let 16- and 17-year-olds vote in general elections, or sign up for the military at an equivalent age. They're not ready for it. Easing them into the democratic process by allowing youth to vote in leadership votes is one thing; initiating them by throwing them into the equivalent of the voting Olympics is another.
Remember, these 16- and 17-year-olds are the same people who can't pick up after themselves, and rest assured it will be the grownups who have to clear away the mess of secession. Only this time the mess will involve long-lasting stains like currency, equity markets, oil supplies and borders.
Having a party and trashing your house is one thing; getting high on the dream of independence and trashing your country is another.
This isn't to say that young people between the ages of 16 and 18 aren't smart enough to weigh the pros and cons of independence. They are, and some have elaborated their views eloquently. But these engaged nerds are in the minority.
For many of these young people, voting for independence will be the equivalent to re-tweeting something on Twitter, or "liking" something on Facebook. Indeed, the Yes side has a lead over No on social channels. The sociology types have come up for a word for this phenomenon: slacktivism, when words aren't followed by deeds.
Slacktivism might be fine for petitions about world peace, but it's not good enough to decide the future of your country.
Come Thursday, the future of the United Kingdom could very well depend on the whims of teenagers. As any parent will tell you, that's an uncomfortable and unreliable place to be.
Andrew MacDougall is a former director of communications to Prime Minister Stephen Harper. He is now the senior executive consultant at MSLGROUP London. Follow him @agmacdougall.Suggest a correction