Nicol Stephen, a figure sometimes mentioned in the context of political leadership, has been laying down the law. He tells us that Scotland's Liberal Democrats will have no truck with any Nationalist referendum on independence unless and until the SNP can pass his patented 50% test. On this point, the serial adulterer of Scottish politics is firm.

It sounds bold: grant him that. Put aside the horse-trading that overwhelms Holyrood and it could even seem - what's a cuddly liberal word? - democratic. Why should the Nationalists be allowed to stage a plebiscite unless, in effect, they have already won the popular vote? Nicol, fancying himself as First Minister - he does not insist on 50% of our support - is all that stands between the Union and destruction. Give the boy a Mondeo.

Menzies Campbell, knight of the realm, supports this strategy. Liberals, famously, can't be doing with referendums, or with coalitions, or with shabby backroom deals or with touting their erratic support in the name of responsible government. Jack McConnell, if he could get the grit from his teeth, would tell you all about it.

Two points arise. One is that Stephen is reserving to himself the right to decide when the people of Scotland can, or more importantly cannot, decide the future of their nation. No biggie, as young folk say. Secondly - and you had better guess at the deleted expletives - who the hell are the Liberal Democrats?

How would it be, for one example, if this voter chose to insist that Stephen and his tribe should earn the right to govern my country by doing something unprecedented, like actually winning an election? This is all he requires of the Nationalists and Labour, after all.

How would it be, meanwhile, if the bold Nicol adopted the ancient Liberal practice of actually consulting his own party? They, ordinary members, are fed up with eking out an existence as Labour's patsies. They could live with the SNP, most of the time. They could certainly live with a referendum on self-determination. Ethically, politically, strategically, that stuff is impeccable. But no-one is asking.

Instead, we see Stephen imposing a test of legitimacy that his own party could never hope to pass. He seems to believe this makes him extra clever. His party has exploited the late Donald Dewar's manipulation of the electoral process with more alacrity than most. That was yesterday. Who granted the LibDems a veto? Who allowed them to become so presumptuous, and so insufferable?

My own opinion is that Alex Salmond would lose an independence referendum tomorrow, or next year, or five years down the road. My guess is that the SNP would be damaged, and damaged beyond repair, if it followed the Quebec route and nagged us, repeatedly, over the big, definitive national question. That isn't the point.

Stephen calculates that the Nationalists can only govern with his support. His own, whey-faced supporters, meanwhile, plant tales suggesting that he is "dangling the keys of Bute House" in Salmond's face. Possibly so: things are becoming mucky at the bottom end of the Royal Mile. But your idiot returns to the idiot's question: what's democratic about any of that?

Why not hold a referendum on May 3 on the blessings, or otherwise, of Liberal Democracy in Scottish life? Has our fishing industry been saved? Has the issue of CIA rendition flights been resolved? Are the LibDems campaigning for, or against, a second Forth crossing? What do they actually think about nuclear power? And do they have a position they could actually name on Scotland's position within the United Kingdom?

Even the political hacks, that affectless bunch, shelter a soft spot concerning the party of no-fixed-intellectual-address. We let them away with murder, much of the time. Liberals, the original political cross-dressers, are always "none of the above". It amounts to inheritance from British political life. So do we encourage the delusion that the Liberals are still the teach-them-a-lesson repository of the harmless protest vote? Not quite.

Stephen assumes, like most of those sheltering under the lea of Arthur's Seat, that the SNP is liable to make progress come May 3. He also guesses - the polls have yet to track the fact - that no landslides will be forthcoming. He's right: put money on it. But the over-promoted LibDem still tacks, trims and adjusts to the perceived prevailing media breeze. Insults towards the SNP are a mere negotiating position. So what follows?

So this. Stephen, astonishingly, abrogates to himself the right to decide how Scotland and Scots should live in the 21st century. He deplores "insults" and then insults us all. He lectures a people, the whole bunch of us, on our obligations towards his minor political cult. Then he solicits our votes.

And with a straight face. A Liberal? Pinch me.

It is an issue, finally, of political legitimacy, born of Scotland's madcap electoral system and our eternal coalitions. It is an issue, equally, born of the odd notion that Liberals are "nice", or "decent" or - in a tight by-election - "well-meaning". Bring back the expletives, nurse. The Liberals' record in Scotland's young government has been deplorable: that's just a fact. Their right to sanctimonious sermonising persists only because no-one calls them on it.

Simplify. Nicol Stephen, the Forrest Gump of representative Scottish democracy, says I can't have a vote on the world in which my child might want to live. Why not? Because life is like a box of Liberal chocolates, apparently. Or a selection of choices. Or "informed" decisions. Or legislative opportunities selected by a mature parliament impeded, in passing, it just so happens, by certain notorious serial opportunists. Called Nicol, mainly.

May 3 is liable to be tedious. A few of us will write screeds and most of the rest of us will stay at home, so the polls insist.

Fair enough: that, too, is a democratic choice. Do not be deluded, though, by the old fiction of Liberal Democrat decency. If we trust his public statements, Stephen is neither liberal, nor democratic nor decent. Seriously.

Did I mention xenophobia?

Big word, lots of syllables, somewhat Greek. It comes up now and then when someone demands your biometric address and your genetic history.

Call me suspicious, but I don't believe for a second that Jamie Stone MSP - as alert as the name suggests - decided to accuse the Nationalists of racism on the BBC just by accident, and just after his leader had demanded an end to egregious political insults. Cover the children's ears: it wouldn't be the Liberals if the race card stayed hidden in an election campaign.

Stone apologised, obviously. That's nice. Nicol Stephen, meanwhile, did not disown the chap who claims mileage for Caithness. Salmond then made a big fuss over the ethnic "slur". But will the SNP ever - and I mean ever - refuse to form a government with the perennially delightful LibDems?

Before I vote, I want to know.

Smarter types than I say this will be an authentically nasty election. I hope so. I am tired of nice politicians. I offer a quaint notion instead: why don't we just vote for the things in which we actually believe? Only the LibDems could possibly object.

Read Ian Bell also in the Sunday Herald.