Last night, I happened to stumble on a Twitter discussion in which Kenny "Devo or Death" Farquharson and Paul Sinclair swapped examples of lessons that the Prime Minister had supposedly learned from the indyref as he plotted his tactics for the European battle. I'm not really convinced that either of them were barking up the right tree. Farquharson reckoned that the Scottish experience had taught Cameron that he needed to have a firm offer of a reformed union before going to the people. The problem here is that the plan for a pre-negotiation on Europe was in place long before the indyref, and I seem to recall a number of people pointing out the blatant contradiction of Cameron's stance (especially when he insisted that it was absolutely essential to get the decision on independence out of the way before discussions on more powers could begin).
Sinclair's suggestion sounded more plausible - that Cameron had learned from Scotland that it's necessary to have a short, sharp campaign to prevent the referendum having an impact on party voting patterns (ie. to prevent Out-voting Tory supporters switching en masse to UKIP in the same way that Yes-voting Labour supporters switched en masse to the SNP). But let me present to you Exhibit A - the Scottish result of the 2014 European Parliament election, held just four months before the indyref...
SNP 29.0% (-0.1)
Labour 25.9% (+5.1)
Conservatives 17.2% (+0.4)
UKIP 10.5% (+5.2)
Greens 8.1% (+0.8)
Liberal Democrats 7.1% (-4.4)
As you can see, Labour did pretty well - at least relative to the SNP's performance. You certainly wouldn't look at that and think they were heading for complete meltdown only a year later. You would also think they were shaping up to at least be reasonably competitive in the next Holyrood election. Opinion poll evidence paints much the same picture - the last few polls before the referendum gave Labour their customary commanding lead in Westminster voting intentions, and gave the SNP a relatively modest lead (of less than 10 points) for Holyrood.
The reality is that the long referendum campaign passed most voters by. It wasn't until a very late stage that Yes voters looked deep into the soul of the Scottish Labour party, and found what they saw profoundly ugly. I would imagine that the set-piece TV debates (including even the one that Alex Salmond supposedly 'lost') played a big part in that, with a senior Labour figure so visibly and miserably making the case for unelected Tory rule in Scotland.
So a short campaign isn't necessarily going to eliminate the risks for Cameron. Having said that, the EU referendum is a very different beast, and the fact that several Tory cabinet ministers are being allowed to campaign for Leave may draw some of the poison as far as Tory voters are concerned. Perhaps the more pertinent question is whether the Tory party itself can hold together after a divisive campaign. The 1975 precedent is inconclusive - although Labour didn't split immediately, many people think the referendum sowed the seeds for the SDP split six years later, as some Labour pro-Europeans realised they had far more in common with their fellow Yes campaigners in the Liberal party than with the likes of Tony Benn.