OH, what a beige campaign it’s been. Elections aren’t Netflix originals, but this one did have some dramatic promise, at first.

Having survived an attempt to oust her at the end of the last series, Nicola faced a shock new challenge from her embittered former mentor Alex. For the first few days, we were all bingeing on it like it was Game of Thrones.

But since then? Nothing. Alba has gone nowhere fast and a blanket of predictability has settled back over Scottish politics. The other party leaders have gamely stepped up to inject some colour by karate-kicking and dancing their way through the campaign, but even Anas Sarwar’s surprisingly adept car park gyrations with a burlesque troupe haven’t been enough to rescue the sixth Holyrood election.

It has felt like just another skirmish in a long war of attrition. The trenches might move a few feet this way or that but the overall map isn’t changing. A pro-independence majority, with the SNP by far and away the largest party, is all but assured.

You have to wonder why it is that the opposition parties have made so little headway. After all, the SNP isn’t ageing well as a party of government. It has a mixed record – some successes but also some notable failures – and the division and intrigue within the independence movement would shame a Renaissance court.

A screenwriter would surely fear that having the party win big after the vicious public splits of the last two months would lack authenticity. Who would believe it?

READ MORE REBECCA McQUILLAN: Independence is a hard sell

Blame for the SNP’s apparent invincibility is usually heaped upon the Holyrood opposition parties, as if they are just failing to ask the First Minister the right questions, but is that fair? There is talent on the opposition benches and the new Labour leader has style and ability. But the system is highly unlikely to give any of them a shot at the big job until the constitutional question is settled.

It can’t have escaped anyone’s notice that this is yet another election shaped by independence, with the SNP raking in the vast majority of pro-independence votes. The pro-UK vote, however, is split three ways, with the Tories and Labour each commanding a sizeable proportion. While they are competing with each other for around half of the total vote share, those parties are destined to aspire only to second place.

As if to underline this reality, Nicola Sturgeon yesterday published a presidential-style plan for her first 100 days.

For the others, what would be the point?

The Herald:

The other party leaders don’t have anything like the media profile of the First Minister. People know and approve of Nicola Sturgeon. They feel she’s handled the Covid crisis much better than Boris Johnson and they’ve see her day in, day out, standing at the podium in her briefing room. I happen to think those appearances have been justified during the pandemic, but I’m not so naïve as to believe they don’t benefit her politically.

It’s not so much the shortcomings of the Scottish opposition parties that explains the current state of the opinion polls, then, but the constitutional faultline, Boris Johnson’s unpopularity and Nicola Sturgeon’s sheer dominance of the political scene.

The Scottish parliament was famously meant to usher in an era of consensus politics, with parties struggling to achieve majorities and being forced to work together across party lines. There’s been less of that than expected in the last decade.

So what’s the answer? That referendum. The irony is that another independence poll, divisive as it would be, would open the way for another era of coalition politics, by freeing people up to vote on matters other than the constitution in subsequent elections.

Let’s say Yes wins another independence referendum: in the wake of euphoria, three things would rapidly follow. First the SNP would have to try and make good on campaign trail promises in a most challenging climate. The economic constraints immediately following independence would likely take their toll on support for the party.

Secondly, the SNP would have lost its raison d’être – the central column that has held up the big tent all these years – leaving erstwhile pro-independence supporters free to cast their vote elsewhere if they wished.

And thirdly, the Achilles heel of the opposition parties – their affiliation with UK-wide parties – would come to an abrupt end. Whatever Boris Johnson or his successor were doing at Westminster, it would no longer be Douglas Ross’s problem.

Independence would also, theoretically, end the SNP habit of deflecting blame by pointing the finger at Westminster for funding shortfalls and other shortcomings.

All this would be likely to make voting patterns much more fluid.

And if the SNP lost a second referendum? Would they just start campaigning for a third one, ushering in another 10 years like the last 10? I don’t think so. Having asked the Scottish people to back independence not once but twice in 10 years, and failed twice, another referendum would be off the table for the foreseeable future. It would be beyond painful for Yes activists. Cue SNP resignations and recrimination. The SNP would suffer the fate of the Tories after 1997 and Labour after 2010. As in those periods, it could be a transformative moment in Scottish politics.

READ MORE REBECCA McQUIILLAN: Sleazy does it for Tories

None of this is to say that the performance of the opposition parties doesn’t matter. The Conservatives tripped themselves up in full public view in March by calling for Nicola Sturgeon’s resignation before she’d been questioned by the parliamentary committee and before an independent report was published on whether she’d broken the ministerial code (she hadn’t). It was cynical and rather foolish. The party still defines itself overwhelmingly by what it’s against instead of what it’s for.

Scottish Labour under Richard Leonard, meanwhile, was the last surviving enclave of Corbynism. By clinging on long after the man himself had gone off to tend his tomatoes, Mr Leonard did his party few favours.

But the seemingly endless domination of Scottish politics by the SNP is about more than opposition party missteps.

Holyrood has impassioned and committed individuals on its opposition benches, but they are stuck snapping at Nicola Sturgeon’s ankles. It may take a referendum to change the voting habits that have defined the Scottish parliament for so many years.

Our columns are a platform for writers to express their opinions. They do not necessarily represent the views of The Herald.