She’s King Herod. She’s Lady Macbeth. She’s Attila the Hun. Nicola Sturgeon has really caught Boris Johnson’s eye. Piers Morgan is more circumspect. For him, Sturgeon is merely “the most dangerous woman in Britain”. This, says Sturgeon, is “possibly one of the nicest things the Mail has ever said about me”.

The newspapers that carried these gentlemanly hysterics, the Telegraph and the Mail respectively, both agree that Sturgeon is a kidnapper, warning the UK on their pages that she is holding the country “to ransom”. The Times eschews such hyperbole, suggesting only that she is only going to hold the UK’s defence to ransom. Gosh. Even if the SNP takes every seat in Scotland – and that’s not beyond the bounds of possibility – it will still only have one in every 13 Commons votes. If Westminster really is this vulnerable, then, really, it’s brought its troubles on itself. Of course it has.

Earlier in this election campaign, the Conservatives were warning that Labour leader Ed Miliband would be in Alex Salmond’s pocket. Clearly, they hadn’t understood the nature of the SNP threat back then. Now, they have Miliband as a helpless marionette, with Sturgeon pulling the strings. Meanwhile, their portrayal of Red Ed as a rabid lefty has been utterly blindsided, because Sturgeon has taken every opportunity to emphasise that she doesn’t think Miliband is very lefty at all.

So what makes Sturgeon so dangerous? It’s because she’s a great politician. But it’s also because she’s an authentic politician. The unionist parties may point their fingers and clutch their hearts, accusing Sturgeon of wanting to break up the union. But what they haven’t been able to do is express with any conviction or urgency why this would be such an awful thing. On the contrary, every time they warn of the dangers of what is happening in Scotland, they might as well announce that they despise democracy, if it strays from the narrow path trod by first-past-the-post two-party politics. And no wonder. Sturgeon has indeed distracted them. They are bogged down, flailing about as they insist that there can be no democratic alliance with the SNP because that’s the wrong kind of democratic alliance.

What Sturgeon has is clarity. It’s Conservative strings she’s pulling really. David Cameron thought that the SNP would weaken Labour north of the border. He thought that would strengthen his own party. Even though he has spent five years in coalition, insisting that it could work, he now seeks to suggest that agreement between two parties can only mean “the tail wagging the dog”.

Did the Lib Dems wag the Tory dog? Sadly, not at all. In the tight embrace of the Conservatives, the Lib Dems were crushed. If the Conservatives really want to display the limits of SNP power in Westminster, their only hope is that Labour can deliver a similar trick with more subtlety. The evidence is that Sturgeon knows this very well. Close, but not too close – that’s her offer to Labour. The last thing Sturgeon would want would be co-option by Westminster.

Sturgeon has already managed to federalise the UK to a degree. The battle is for English votes and English seats. England can now see the political stalemate that Scotland has been able to see for decades now. That’s why she is dangerous. She reveals the truth about British democracy. Sturgeon is dangerous to the political classes, because she is offering voters a clearer view of how the political classes work.