AS the election campaigning progresses, it’s becoming increasingly obvious that the arguments deployed by the Union-supporting parties have waved goodbye to logic and no longer make any sense whatsoever.

There has long been a philosophical gap between the Scottish and the UK parliaments. It’s not buying into the myth of Scottish exceptionalism to recognise that the Westminster Parliament operates within a completely different moral code to its equivalent in Holyrood.

Take the recent furore over whether or not Nicola Sturgeon broke the ministerial code. There was general agreement that she would have been morally required to resign had she been found by QC James Hamilton’s independent inquiry to have done so. Indeed, the First Minister herself suggested she would have had to do exactly that.

In Westminister, politicians seem to break the code as casually as they order a carry-out pizza. The very long list of those accepted to have broken the code include Home Secretary Priti Patel, Health Secretary Matt Hancock and probably the Prime Minister Boris Johnson himself.

Sir Alex Allan, a former independent adviser on the ministerial code at Westminster, recently suggested there had been incidents “which prima facie appear to involve a breach of the code but which haven’t been referred to the independent adviser”.

In other words, due process has been interfered with.

Here in Scotland, former first minister Henry McLeish resigned in November 2001 over allegations he sub-let part of his Westminster constituency office without registering it in the parliament office.

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Wendy Alexander resigned as Labour leader in June 2008 after accepting an impermissible donation from a businessman who was not registered as a UK donor, and after a separate development which saw her reported to the procurator fiscal for failing to declare donations as gifts. She insisted a pending inquiry would find she had done nothing wrong, but said the allegations had become a distraction and she had to quit.

I’m not suggesting these resignations were over trivial matters, but they don’t stand comparison to the MPs expenses scandals, for instance, from which most politicians emerged unscathed.

Tony Blair joined with George Bush in the illegal invasion of Iraq, supporting a war on the basis of Iraq having weapons of mass destruction which had not been found and for which there was no evidence. The Chilcot Inquiry into the war found Blair overstated the threat posed by Saddam Hussein and sent ill-prepared troops into battle and yet the former prime minister faced no consequences.

When Nicola Sturgeon faced allegations about her treatment of allegations against Alex Salmond, she gave evidence to an enquiry for eight hours and could easily have lost her job.

The point I’m making is that the Scottish and Westminster parliaments operate within very different moral frameworks and have done so since the Scottish Parliament was established in 1999. As a result, Scottish politicians act and think very differently to their counterparts at Westminster, even within the same party. And that’s increasingly becoming an existential crisis for pro-Union parties with representatives in both camps.

Take, for example, the Scottish Conservative leader Douglas Ross, who during the second televised leaders debate on STV on Tuesday had to grapple with this awkward problem. Scottish Tory MSPs had voted with their opponents at Holyrood to put into Scottish law the United Nations Convention on the Rights of the Child.

Fair enough, you might say, surely not even the most right-wing zealot among Tory ranks would object to measures so obviously designed to protect children.

Wrong. Westminster Tories are about to take legal action to stop the Holyrood move.

When Nicola Sturgeon asked Ross to justify Westminster’s actions, he simply couldn’t do it and dodged the question.

Or rather, he toed the patently untrue party line that Westminster was simply trying to clarify a procedural move, which amounts to the same thing. There are simply no mental gymnastics which could explain away so fundamental a difference in attitudes that it did not even occur to Westminster Tories to try to block this protection of basic human rights.

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TAKE, for another example, Scottish LibDem leader Willie Rennie, a passionate campaigner against Brexit. Rennie believes two principles to the very core of his being. The first is that Scotland should remain in the UK. The second that the UK should rejoin Europe.

The trouble for him is that these are diametrically opposed ambitions.

There is no party likely to form a UK government which aims to return to the EU fold. Not the Tories, not Labour under Keir Starmer, and certainly not the LibDems, whose UK leader Ed Davey said as recently as January that his party was no longer interested in the UK rejoining the EU.

When confronted with this irreconcilable conflict by Nicola Sturgeon in the leaders’ debate, Rennie could only fall back on a risible suggestion that he could somehow persuade Boris Johnson to reverse Brexit.

There is no other politician in Holyrood or Westminster who believes that will ever happen unless we discover an alternate universe.

Then there is Labour’s new leader in Scotland, Anas Sarwar, hopelessly shackled to Keir Starmer’s refusal to countenance a second independence referendum and his vow to stand on that platform in the current election campaign.

Starmer made that vow in September last year, before the party’s then Scottish leader

Richard Leonard had resigned. He had not changed his opinion last month, after Sarwar was elected. His argument that the independence issue was focusing on “the wrong debate” has even been half-heartedly adopted by Labour’s Scottish leader.

But Anas Sarwar knows, even if his Westminster boss does not, that if Scotland returns the majority of pro-independence MSPs in May that looks almost certain, it would be profoundly undemocratic to stand against that decision.

Starmer may not have a deep ideological reaction to standing side-by-side with Boris Johnson to deny Scotland its democratically expressed wish, but I’m willing to bet that Anas Sarwar would find that very difficult.

There is something else that all opposition leaders in Scotland have in common, and that is a commitment to devolution. Even Douglas Ross claims he clashed with Boris Johnson’s statement that devolution had been a “disaster” for Scotland.

Yet it’s now crystal clear that the Tories in Westminster want to dismantle the sharing of power with Scotland. They have no respect for Holyrood and ridicule the MPs we elect to the UK Parliament. They want to fly the Union flag over all public buildings and stick it on those new projects Westminster will pay for with money they robbed from the Scottish budget.

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Make no mistake, if the Tories at Westminster have their way, the Scottish Parliament will be constantly attacked and its powers continually diluted until they virtually disappear. On past and present performances, opposition parties at Westminster will either collude with them in this aim, or at least lift not a finger to stop them.

Whatever their views on independence, politicians north of the Border will be forced to take a stand to stop the actions of the pro-Union parties or be complicit in the death of devolution. They simply cannot on the one hand portray themselves as democratic and on the other stand united against the clearly expressed wishes of an entire country. That tension within the pro-Union parties in Scotland will rip them apart.

The bus has already departed for destination indyref2. The opposition MSPs in Scotland have a choice: either catch up with it and get on board, or find themselves imprisoned in parties which have abandoned all pretence about caring what Scotland thinks, with the inevitable electoral consequences.