There’s general agreement that next week’s British election is going to be the one that breaks tradition of a system able to deliver clear-cut results.

William Bowe in Crikey yesterday described the country as a square peg in its electoral system’s round hole; Patrick Dunleavy at The Conversation said the impending result amounted to a refutation of Duverger’s Law.

To understand what’s going on here, it’s necessary to start with last year’s Scottish independence referendum. Scots voted against independence, but the “yes” vote was a respectable 44.7%. It’s not surprising to find that that’s a good fit for the Scottish National Party’s vote in the last Scottish election (in 2011), 45.4%, given that it was the only major party supporting independence.

The anomalous figure, until now, has been the SNP’s vote at British elections: in 2010 it managed only 19.9% in Scotland, which equated to 1.7% in the UK as a whole.

But now, whether due to the referendum or other causes, nationalists are evidently bringing consistency to their voting behavior: by the start of the election campaign, opinion polls had for some months been showing a SNP vote in Scotland in the mid-40s.

And under first-past-the-post voting, with three different opponents, 45% or so of the vote will win you a large majority of the seats.

SNP gains will mostly come at Labour’s expense, since it currently holds most of the Scottish seats. And since the SNP is also on the left, it’s a natural fit with Labour as a coalition partner.

As I said earlier this month, even from an anti-independence point of view, “there’s never been a better time to bring the SNP into government”.

But the reaction during the campaign has been completely different — so much so that it raises the question of whether Britain can be better understood using a completely different model. For example, Israel.

In last month’s Israeli election, Prime Minister Benjamin Netanyahu outperformed expectations by means of a last-minute scare campaign based on the idea that Israeli Arabs (who of course are citizens with full voting rights) were voting in record numbers, and that it was necessary for his Likud supporters to turn out to counteract their influence.

Implicitly, the message was that Netanyahu’s centre-left opponents might form government with the support of Arab parties (never a likely prospect) and that this would be illegitimate and un-Israeli.

Britain may seem a long way from the conflict-ridden Middle East, but the Conservative Party’s rhetoric in relation to the SNP has distinct echoes of Netanyahu.

With not much else going its way, the Tory campaign — masterminded, it’s said, by Australia’s own Lynton Crosby — has seized on the Scottish issue, forcing both Labour and the Lib Dems to disclaim, in increasingly explicit terms, any intention of relying on SNP votes.

The argument is that a government dependent on the SNP would be illegitimate — in effect, that the views of Scottish voters don’t count (unless they vote for English parties) and shouldn’t be part of the calculation of who gets to form government.

It’s what the Tories argued in the early 20th century in relation to Irish votes.

The last few days’ worth of polls suggest that the Tory strategy is having some impact in England, maybe pulling back a couple of percentage points of support from Labour and/or the UK Independence Party.

But it’s also having an impact in Scotland. Scottish voters, unsurprisingly, don’t like being de-legitimised, and their reaction has been to swing even further to the SNP, which is now recording more than 50% of the Scottish vote — raising the prospect that it could win every one of Scotland’s 59 seats.

The Tories have always faced a paradox in relation to Scotland (as a century earlier they did with Ireland): their political ideology was based on keeping the Scots in the union, but their political interest would be better served by having them leave.

And the more they stressed the unionist ideology, the more their electoral fortunes in Scotland declined, and so the stronger their contrary political interest became.

Cameron’s rhetoric is an attempt to square that particular circle. But by defending such an exclusive sort of nationalism — just like Netanyahu —  he’s potentially hastening the thing he claims to be fighting against. He’s helping to destroy any loyalty the marginalised group might feel to the “nation” — which of course isn’t really their nation at all.

If the strategy somehow delivers Cameron a majority, there will undoubtedly be a push for another referendum in Scotland. But if, as seems much more likely, the SNP emerges with the balance of power, the English parties are going to have to learn to deal with that.