Salmond's strategists, packed into a third-floor office suite behind the Scottish Parliament fear that – in the words of one senior Nationalist – “we have gone too early”. That Labour may now plausibly play the underdog card, and SNP votes may be inclined to stay at home thinking that it's in the bag.
It doesn't help that this is the second poll in a week to give the SNP a commanding lead over Labour. The IPSOS Mori poll for The Times last week gave the SNP an 11 percentage point lead over Labour on the first vote and a ten point lead on the regional list vote.
Translated into seats, both polls give the SNP the same result: 61 seats, just four short of an overall majority. Labour would have 42 seats, according to YouGov or 45 according to Mori. For a party that had hoped to retake Scotland, as stage one of a national comeback, it would be a humiliating result.
Furthmore, with both polls giving the Greens enough seats to make up the difference to the majority figure of 65 (and with the Greens backing an independence referendum) it does now seem that Alex Salmond’s dream of putting the independence question in a referendum may be within reach.
The irony is that the devolution system was designed (by the three unionist parties) as a device to "kill nationalism stone dead" (in the words of George Robertson, Labour's Shadow Scottish Secretary in the run up to the 1997 election). Instead, Salmond is now looking at his second term and dreaming up the language for his independence referendum.
Donald Dewar drew up this particular electoral system specifically to stop the Nationalists gaining an overall majority. The list system is designed to prevent parties from gaining an overall majority; it is really very, very difficult indeed to achieve that. (The last party to get over 50 percent of the Scottish vote were the Conservatives in 1955).
The Holyrood voting system was Dewar’s ultimate safety valve. He knew that, if he could stop the SNP from gaining an overall majority, then he could probably stop them ever putting independence to the people.
What he didn't factor in, though, was the influence of the smaller parties and while a formal coalition between the SNP and the Greens is very unlikely (the Greens demand such things as tax rises, no coal-fired power stations and no new Forth Road Bridge as conditions of coalition) a confidence and supply agreement is not out of the question. This could include a deal to vote through an independence referendum.
But there is another, bizarre subtext to all of this. The SNP is doing well because Scots, by and large, think Mr Salmond is the best at standing up for Scotland. Many unionist Scots are prepared to back him precisely because he has not pushed his independence agenda too hard. They believe they can vote SNP with impunity because independence isn’t really a viable prospect with minority government in Scotland, and that they can always vote against it in a referendum.
There is an important distinction, often lost in Westminster, between SNP support and support for independence. The latest poll for today's Sunday Mail newspaper shows 33 percent support for independence: pretty much where it has been for the last decade. But so many Scots are now backing the SNP on this basis that, perversely, independence (or at least a referendum on independence) may now be, almost, within reach.
There is, as that senior SNP source revealed yesterday, a real possibility that the SNP might have “gone too early” and that complacency will set in among supporters faced with such extraordinary poll leads but another source also made clear that there was “more to come” in the next two weeks.
That means the SNP expect more from The Sun, which came out with such gusto to the SNP cause last week, and they intend to get more from the £500,000 donation from bus tycoon Brian Souter.
The SNP has turned into a smart campaigning operation. Westminster leader Angus Robertson is running its campaign extremely well so, although there are well-grounded fears about complacency, Labour shouldn’t expect their opponents to implode, far from it.
As for Labour. Its campaign is in a mess. It has been badly-run from the start. It has chosen a message (vote Labour to stand up to Tory cuts at Westminster) which has not resonated nearly as well as the SNP’s message (vote Salmond to stand up to Tory cuts) and there is now audible back-biting, bitching and blame shifting going on within the Labour camp.
To cap it all, the one image of the campaign which will stand out was of Scottish Labour leader Iain Gray barricaded into a sandwich shop in Glasgow Central Station being pursued, not by anti-Labour activists, but by anti-cuts campaigners who, he decided, he had better not face.
This was supposed to be the campaign which saw the implosion of the Lib Dems. That has happened, but it has been trumped by Labour’s effort, which has seen the party squander a 15 point lead.
The only comparison is Rory McIlroy's epic collapse at the Masters this year, just don’t expect Labour to lose with anything like the grace that the young Northern Irishman showed.
Hamish Macdonell is a political commentator and author of Uncharted Territory: Scottish Devolution 1999-2009.
UPDATE: The SNP has a press release with new figures. No response from Labour yet.