EDINBURGH, Sept 16 (Reuters) - Scotland's independence campaign has stoked strong passions on both sides but with just two days until Thursday's historic referendum, it is the quiet waverers who may hold the balance of power.
Scotland decides on Sept 18. whether to sever centuries-old ties with the rest of the United Kingdom. Recent polls have narrowed dramatically and show the vote is too close to call.
The United Kingdom's fate may rest on a group of undecideds which could constitute as few as 500,000 people out of an electorate of more than four million. They are weighing up the economic uncertainties against the pull of sovereign statehood.
With claims and counter-claims made by both sides over how the economy, welfare and health care will be affected, some voters who are most in need of persuading feel little the wiser.
"My heart says yes but my head says no. I guess it will come down to how I feel on the day," said Anne from the town of Lochgelly, north of the capital Edinburgh.
She declined to give her full name.
"It's such a risk, and you can't know what's going to happen. When even businessmen disagree over the impact it's going to have, how are we meant to know?"
As the campaign enters its final stretch, two factors will decide the country's future: whether those who have expressed a firm preference think again and whether the undecideds come off the fence and if so which way.
Opinion polls show the elderly will swing heavily towards the "No" camp and will turn out in high numbers. But previous strongholds for the pro-unionists - the female vote and opposition Labour party supporters - have wavered.
Ben Page, chief executive of polling group Ipsos MORI, said the undecideds tended to be women and young people.
Polls suggest 10 percent or more of the electorate has yet to make up its mind but Page told BBC Radio most of them had essentially decided and that only about four percent who were certain to vote were genuinely unsure about how to.
If true, that leaves a small pool for each side to target. The problem could be finding them.
Many Scottish residents declined to talk to Reuters about their intentions in recent days, a reticence that makes it difficult for pollsters and campaigners to divine their intentions.
At Edinburgh's International Airport, where Scottish nationalist leader Alex Salmond was campaigning with pro-independence businessmen on Monday, public displays of support for either side were in short supply.
"I'm undecided. I've been working a lot, so I missed the TV debates. I haven't had a lot of time to think about it," Geoff, who works at the airport, said.
"The economic side of it is important to me, and I'm leaning towards no. These politicians always promise you the sun, the moon and the earth, but I don't trust them."
Simon, 24, works in an Edinburgh bookshop and also declined to give his surname. He is one of the genuinely torn.
"I'm leaning towards yes. I'm very much in favour of self government. A lot of risks seem to be scare stories," he said. "But my doubt is whether we can afford it. I need to do more research. It's only a few more days so it's going to be a lot of online reading into the early hours of the morning."
The reluctance to speak up is emblematic of what some academics say may be a "shy no" vote - people who won't admit in public that they are put off by the risks of independence but will vote against in the privacy of the ballot box.
In Glasgow, William Andrews, who will vote for independence, was unconcerned. "They say there's a silent majority voting No. I really don't see any evidence of that," he said.
Glasgow has proved to be fertile ground for the independence campaign and which way traditional Labour party voters swing, especially in Scotland's biggest city, could be decisive.
Overall, while still too close to call, the poll of polls puts the "No" campaign on 51 percent, "Yes" on 49. If accurate, that means the independence camp has to swing more support its way with time running out.
"Unless something dramatic happens in the next three days, a No victory is now the more likely outcome," said Peter Kellner, president of YouGov, the polling organisation who's survey a week ago putting the "Yes" camp briefly ahead sent panic rippling through the British establishment.
"Note the word 'likely': it's not certain ... But the momentum favouring Yes, which caused such consternation last weekend, seems to have gone into reverse," Kellner said.
With the momentum clearly with the independence campaign in recent weeks as polls narrowed sharply, it hoped the "don't knows" would eventually break in their direction in disproportionate numbers.
Polling experts say historic parallels, including the 1995 Quebec referendum, suggest otherwise.
Stephen Fisher, Associate Professor of Political Sociology at the University of Oxford, looked at 16 constitutional referendums held worldwide over the past 40 years and found that in 12 of them, the average "Yes" vote reflected in opinion polls was not delivered in the voting booths.
"Research from Canadian electoral reform referendums suggests that Don't Knows split disproportionately towards the status quo," Fisher said in a blog posted on the non-partisan website "What Scotland Thinks".
"This does seem more likely than a split in the other direction, though an especially big movement from Don't Know to No in the last hours of the campaign also seems unlikely."
With two days to go, the basic equations of hope versus fear, heart versus head continue to hold sway.
For Salmond, Thursday's vote is a "once in a lifetime opportunity". Some on the other side of the debate are also urging voters to look at the big picture.
"Shrinking a nation's relative size and setting it adrift in the global economy is a bad decision," former Bank of England policymaker Adam Posen wrote in the Scotsman newspaper.
"Any gains from supposed independence would come with deep losses in actual autonomy. Those losses would heighten insecurity and vulnerability of households across Scottish society." (Editing by Mike Peacock) )