Why small differences are crucial when politicians are fighting for supremacy

He described a phenomenon in which "adjoining territories" are "engaged in constant feuds and ridiculing each other" on the basis of "details of differentiation".

To Freud it was represented a "relatively harmless satisfaction of the inclination to aggression", and indeed this need to exaggerate often small differences still dominates politics in general and Nationalism in particular.

Take a recent survey commissioned by the prolific blogger Wings Over Scotland, which deliberately contrasted public attitudes in Scotland and the rest of the UK, one assumes in the hope of justifying a key narrative of the referendum (i.e. that Scots think differently from those in other parts of the country).

Instead he (the Rev Stuart Campbell) found that, overall, Scots agreed with their counterparts in the rest of the UK on most major policy issues, "varying only in degree", a conclusion backed up by several other social attitudes surveys over the past couple of decades.

Even in areas where Campbell reckoned Scots differed "quite a lot" - on nuclear weapons, the monarchy and workfare - the gap wasn't that large. On the monarchy, for example, two thirds of Scots agreed "Britain should keep the monarchy" while in rUK the proportion was three quarters - both sizeable majorities.

On immigration, meanwhile, 69 per cent of Scots agreed there was "a problem with too much immigration", compared with 71 per cent in rUK. Bizarrely, Wings concluded this near identical finding was driven "by Scotland's lack of a true native media" (clearly he can't buy the Herald in Bath), even though most Scottish newspapers have long pursued a more liberal editorial line on immigration.

Most striking were the poll's findings on Trident. When asked if the UK "should continue to have nuclear weapons" 44 per cent of Scots agreed compared with 51 per cent in rUK, leading Wings to conclude that Scots "don't like having Trident in their own backyard", even though more do than don't.

This last finding illustrates well the often-significant gap that exists beyond political discourse and public opinion. Throughout the referendum the SNP gave the impression that Scotland was one giant branch of the CND, whereas in fact the biggest chunk of Scots agrees more with the new Scottish Labour leader Jim Murphy on the nuclear deterrent than they do with Nicola Sturgeon.

I've described this many times as the great referendum paradox, that as attitudes in Scotland have come to resemble those in the rest of the UK more closely the demand for independence (premised on irreconcilable differences) reaches historic highs. On-going polling for this May's general election, meanwhile, shows no let up when it comes to electoral behaviour, where the differences are neither small nor narcissistic.

Yesterday a Panelbase poll showed that on current voting intentions Scottish Labour would lose half its seats with the SNP adding an impressive 29 seats to the half dozen they currently hold. The Scottish Tories would gain just one extra MP while the Liberal Democrats would lose all but two of the 11 constituencies secured at the last general election in 2010.

Later this month will mark the 50th anniversary of the death of Winston Churchill, and with him a very different political era when the two major parties (Labour and the Conservatives) could hoover up more than 90 per cent of the popular vote and smaller parties like the SNP and Liberals were fringe political forces. Those days are long gone.

Indeed, the remarkable rise of the recently departed Jeremy Thorpe and his small band of Liberals in the general election of February 1974 represented a decisive shift to a new electoral age in which the two historically dominant parties couldn't count on majorities and smaller parties became increasingly mainstream.

Thus the forthcoming election continues that trend, with Labour and the Tories each fighting over little more than a third of the popular vote, the Lib Dems likely to decline sharply (though still well above historic vote shares) and the SNP on the cusp of surpassing its October 1974 tally of 11 MPs and 30 per cent of the vote.

In that context no party can afford to fight a conventional campaign, not least in Scotland. The Conservatives have already reheated a message dating back to the Churchill era ("Life's better with the Conservatives, don't let Labour ruin it") while north of the border the SNP has fallen back on its tried-and-tested line about a strong band of Nationalists holding the balance of power at Westminster.

Only this time that SNP cry seems a lot more credible. What the polls cannot really detect, however, is the prospect of tactical voting. Back in the 1980s Labour, the Liberals and SNP actively encouraged this in order to oust incumbent Tory MPs, and although there is actually limited evidence that occurred on a large scale, this time round I wouldn't underestimate it.

Anecdotally, I've spoken to several Unionists of different political hues who plan to vote for whomever they judge capable of preventing an SNP win. Polls showing the Nationalists storming ahead can only fuel this phenomenon, for just as it's likely that now famous YouGov referendum poll giving Yes its first lead scared and motivated Unionist-minded folk into voting No, the prospect of 40 or 50 SNP MPs could have a similar effect.

The SNP is also more vulnerable than might at first appear on the policy front. Last Thursday's First Minister's Questions gave an intriguing glimpse of Scottish Labour's election attack lines, chiefly the oil crisis and the prospect of the Barnett Formula being abolished should the SNP make "Home Rule" or fiscal autonomy a condition of supporting a minority Labour Party at Westminster.

In response the First Minister looked uncharacteristically rattled, failing to address either Kezia Dugdale's "bin Barnett" charge or indeed an ongoing barrage about the falling oil price. Given that the economics of independence played a major role in last September's majority No vote, it makes sense for Scottish Labour to carry on, as Peter Mandelson once put it, "punching the bruise".

Where Alex Salmond might have been able to glide over uncomfortable details while dazzling his opponents with a lifetime's accumulated oil jargon, Nicola Sturgeon is markedly less willing to do so. To argue that Scotland wouldn't have been independent until 2016 so the oil price somehow doesn't matter is scarcely adequate, much like the First Minister's belated call for a tax cut in order to stimulate activity.

Even so, the SNP is in a remarkably strong position less than four months from polling day. Jim Murphy, meanwhile, seems intent on reviving a long tradition of "Unionist Nationalism" by picking fights with what he calls "London Nationalists", and even his own leader to highlight the point that Scotland, as he claimed at a recent lunch with journalists, "is different".

Or, as Wings Over Scotland put it, "the same but different"; even small differences can become important when politicians are fighting for supremacy in an increasingly complex political context.