Aidan Kerr believes constitutional politics is no longer the preserve of Scotland's freedom fighters and has now thoroughly embedded itself in everyday political life.

He is of course right. How did you vote in the referendum? has replaced What school'd you go to? as the question most likely to lead to an arrestable offence.

The last general election bore this trend out. While the SNP took just under 50% of the votes across the country, they got 94% of the seats, solidifying mainly around the referendum results. In most constituencies, however, the SNP could have been beaten into second place if only the "unionist" opposition had united around one "unionist" candidate.

This is of course also correct. It's mathematical fact.

This effect, where the primary political divide is national identity, has been dubbed by Aidan "Ulsterisation", hinting at the deep nationalistic divides in Northern Ireland, which are so fundamental they are legally embedded at Stormont. He says the SNP plays the constitutional game better than their opponents. They do but then they have been practicing for longer.

Plus, when you are the only real "nationalist" party wearing that label (I don't know how comfortable Greens and RISErs would be with the term) there's not much of a game to play.

On the other side, Aidan rightly points out there are three big "unionist" parties fighting for the other 55% of the electorate. In a first-past-the-post election, the united 45% will always beat three 18%s. He concludes that over time we will see a unionist plan develop, slowly and consciously, to allow a "Unionist candidate" to stand against the nationalist menace unopposed.

In this, Aidan has overlooked two fundamental points.

The first is that, bar those at the far ends of the spectrum, most people are not that wedded to their constitutional position. It is generally accepted that the SNP won their majority in 2011 not on the promise of independence but on the impression of competence. The NHS had held up; policing was solid and education results were steady. Free prescriptions and abolishing bridge tolls made Scotland feel... Scotlandier. Nothing fell apart on their watch.

While the 2016 election is perhaps too close to the referendum for the constitutional divisions to have sufficiently healed, the SNP's reputation for competence is no longer untarnished. The education secretary is heading for a face-off with the teachers' unions; Police Scotland seems to limp from scandal to scandal with no one watching the watchmen; and while the SNP have set the most ambitious targets for our NHS, they are increasingly not being met. Not even the new Glasgow Southern super-hospital is enough to assuage the doubters.

With tax powers coming to Holyrood, "Westminster cuts" will soon lose its potency as a diversionary charm. Whether the SNP government can ride the William Wallace wave for another five years is not clear. There is only so long the constitutionally uncommitted middle can overlook a rough today on a promise of a better tomorrow.

But the second reason, and one that is perhaps a little more important, is that while Scotland has "unionist" parties, it has only one "Unionist" party. The Tories believe in the Union for the Union's sake. It is in their full Scottish name: The Scottish Conservative and Unionist Party. The Union for a Conservative is an inherent good.

For the other two parties, unionism is not quite so clear cut - it is a different kind of unionism. The Liberal Democrats are at their heart not a unionist party but a federalist one. In the long-standing Liberal tradition, they want neither independence nor union, but something which lies in between. Together is better than apart, and more likely to lead to their preferred outcome, and so they prefer union for the time being.

And for the Labour Party, the Union isn't a goal itself but a possible route to outcomes. The line from clause four of the party's constitution, that "by the strength of our common endeavour we achieve more than we achieve alone", is the definition of Labour politics, from the NHS to public education. It follows, then, that it is better to improve 64 million people's lives by 25% than five million people's lives by 75%.

The tensions and conflicts the party has experienced, and the tightrope Kezia Dugdale must walk, is that Labour members and supporters are not universally behind this. Note though that Labour-Yes voters tended not to be against the Union per se but against what the UK was and still is - an austerity-driven, Conservative-led country. Independence seemed to them the fastest escape route.

In the same way Green-Yes voters were quick to clarify they were "not a nationalist", to describe all No voters as "unionist" is to overlook the very real divisions between them. Unless and until there is a clear, single, and well-defined understanding of what "the Union" means and what it is for, an ideal which is shared by the "unionist parties", a Scottish unionist pact and an Ulsterised Scotland will have to overcome deep-rooted political instincts to be realised.

Commentary by Paul Cruikshank. He is a 23-year-old Glaswegian with a law degree and a west coast bias. He's a Labour member, tweets as @PAShanky, and blogs at pashanky.wordpress.com on politics, law and television. He is originator and curator of the #HandWatch hashtag.