David Cameron and Alex Salmond have thrown themselves into the final three-days of the Scotland referendum campaign pushing the very same message: "This is forever."
In his final appearance before the poll, the prime minister declared: "There's no going back from this. No re-run. This is a once-and-for-all decision. If Scotland votes Yes, the UK will split, and we will go our separate ways forever."
It is a sentiment shared by Salmond, from a very different perspective, and both men clearly believe the stark, no-going-back pitch will work in their favour.
Cameron thinks it will combat the short-term, anti-Conservative fever gripping some voters who, he previously claimed, wanted to kick the "effing Tories".
Salmond, on the other hand, believes the idea that independence will be off the agenda for "a lifetime", at the very least, will be enough to stiffen the spine of those waverers at the prospect of perpetual Westminster rule.
Neither of them have anything much new to say over the final three days and neither can be sure exactly how such a plea will actually influence individual voters.
But, now all the arguments have been deployed, they agree that the Scottish electorate need to focus its sights beyond immediate concerns, fears and even hatreds and consider what sort of nation they want for their children, grandchildren, great-grandchildren and beyond.
They almost certainly secretly agree on something else; that whatever the outcome is on Friday morning, it needs to be decisive for one side or the other.
The prospect of a small majority for either campaign, which the polls seem to suggest is possible, is seen by many MPs on all sides in Westminster as the very worst possible outcome.
It would immediately undermine the very notion that the vote was "forever" and lead to inevitable demands for a re-run by the losers and cries of "bad losers" from the winning side.
There are also worries the ill-temper, even violence that has allegedly surfaced on occasion during the campaign might erupt into something worse.
Alex Salmond has claimed many times that the "no" campaign had attempted to intimidate and bully Scottish voters with dire threats over the currency, the economy, jobs and so on.
But the "no" campaign has now claimed there has been physical bullying and intimidation from nationalists, with Scottish Secretary Alistair Carmichael insisting: "The person who could stop it all, who could pull the heat out of this is Alex Salmond."
The first minister brushed it all aside claiming he, too, had experienced a little of such behaviour from the "no" campaign but that the overwhelming tone of the campaigns had been peaceful and positive.
As Scotland's "day of destiny" looms, feelings are understandably beginning to run high. A decisive result is needed to ensure the legacy is not one of seething resentment and a feeling from either side that they have been cheated.