FOR every action there’s an equal and opposite reaction, so goes one of Newton’s laws of motion, yet it also has its political equivalent where actions have consequences, and not always what was intended. And we’re seeing that at the present moment in the independence debate, where the actions of the UK Government and Unionist supporters are making breaking free of Westminster positively desirable for some Scots and less unpalatable for others.

That’s been seen in recent days with comments from The Herald’s own Fidelma Cook advocating it and even the Scottish editor of the New Statesman and former Herald columnist Chris Deerin warming to modern Scottish nationalism.

Does it matter? Of course it does, as much in politics as in a physics exam, for the next referendum will be decided not by those who are implacably committed one way or the other and inherently hostile to independence or the Union.

Instead it’ll be swung and won by those who neither lie awake at night dreaming of its coming nor wake up in a cold sweat having had nightmares about independence. Last time they were unpersuaded and saw too many obstacles and too few answers, the risks too great and the benefits too few. But that seems to be changing and it’s got more to do with what’s being done by the Unionist camp than any campaigning by advocates of change. It doesn’t mean that it’s all over bar the counting, far from it, but it does mean its game on for the next one.

The surge in SNP membership also testifies to that, as it appears than around 10,000 have signed up to a party that already dominates in Scotland and even dwarfs some in the UK.

Again, that’s got less to do with the actions or attributes of the party itself but speaks to the frustration and anger felt by many about the actions of the UK Government. Frankly, the SNP has been rather inactive and the Scottish Government equally timid. Taking out a membership card is more an expression of outrage at our present rulers than a declaration of faith in Scottish advocates.

All of this put me in mind of reading the biography of John Costello who was the Irish Taoiseach who declared the Irish Republic in 1947, ironic for he was no ardent Republican. The book was even titled The Reluctant Taoiseach as he’d entered into office more by accident than design. Other contenders including Dick Mulcahy and Sean McBride, both with sterling service to the cause of independence, were unacceptable to the other parties in a coalition forged to oust Eamon de Valera and Fianna Fail. So it fell to Costello who seemed aggrieved at having to forsake a lucrative and enjoyable legal career that he ran in conjunction with his political forays.

The cause of Irish independence and republicanism wasn’t something that he had espoused. He wasn’t involved in the Easter Rising and indeed the book reported he had been playing golf when the Dublin post office was first taken and seeming aggrieved at his journey home being interrupted by a road block. Though a home ruler and a supporter of John Redmond and the Irish Parliamentary Party, he belonged to a Catholic middle class who believed that after the First World War was concluded home rule would be granted and “political, economic and social status” would come. Ardent Republicanism was not only undesirable but potentially damaging. So he, along with many others, wasn’t involved in the War of Independence or even the Civil War that followed it but he still ended up supporting the Free State and ultimately the Republic.

That didn’t happen because he was persuaded by either the likes of James Connolly or De Valera, for he was most certainly not a socialist nor a die-hard republican, but because the actions of the British made it so. When the IRA under Michael Collins and Mulcahy were fighting he was working in the law courts and appears not to have had any involvement in the parallel republican courts that were initiated. But for him and others British rule became more unpalatable than taking charge of their own affairs. Just as the British marched their troops to the treaty ports deciding that opposing independence, of sorts, in the Free State was no longer worth it, many like Costello walked towards taking charge of their own destiny disgusted at the brutality and incompetence of continued British rule from Dublin Castle.

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Now Ireland and Scotland are vastly different entities but it does show that it’s not just the actions of those who advocate a cause but the behaviour of those who oppose it that matters. Post Brexit Britain is no longer the land many thought it was when they voted to stay in September 2014. Instead, xenophobia and triumphalism have been allowed to flourish. The risks of separation are now greatly overshadowed by the threat of leaving the EU. Doubts over a Scottish currency are muted by the decline of sterling. Remaining in the UK seems ever more uncertain, if not positively dangerous. The thought of a Boris Johnson – never mind Jacob Rees Mogg – Government causes sleepless nights for many.

It's not simply the power grab but the actions and even language of the UK Government that’s worrying. The institutionalised cruelty in benefits and the war-mongering in foreign policy. Disparaging European partners and cavorting with despots and demagogues. Even the supposed representatives of Scotland in the Union are not just wrapping themselves in the Union Jack but positively belittling the land they’re supposed to cherish and represent. The hostility towards not just Scottish nationalism but almost anything Scottish has been hugely counterproductive with those who were comfortable in being Scottish but remaining in the UK.

Of course, it doesn’t mean it's all over as the cause of independence has still to be won. The UK would almost certainly depart from the remaining six counties in Northern Ireland if they weren’t beholden to DUP votes. That won't happen here. The UK is not simply going to fade away. But what’s clear is that the certainties of British rule are fading and the risks of Scottish independence no longer so unacceptable.