The events of last week brought to mind that great satirical song-writer Tom Lehrer. In one memorable song he poked fun at National Brotherhood Week, an annual event intended to make all good Americans put aside their differences, of class, religion and ethnicity.

“Oh, the white folks hate the black folks, and the black folks hate the white folks,” it began (as offensively as it meant to go on). “To hate all but the right folks is an old established rule.”

Of course Lehrer’s point was that it was a fiction, that America – and most other nations in the world – were in fact riven by deep divisions that couldn’t possibly be solved by holding hands and thinking positive thoughts.

So the tune went through my head as I watched the SNP and Labour tear strips off one another over the latter’s plan to raise income tax, which was one in the eye for the Civic Scotland types who earnestly predicted that devolution would usher in “a new kind of politics”.

Indeed, Lehrer might have been writing about Scotland with another line: “Oh, the Protestants hate the Catholics, And the Catholics hate the Protestants, And the Hindus hate the Muslims, And everybody hates the Jews.” The equivalent in Scotland being the hated Tories.

There was almost something brutally impressive about the swiftness with which the SNP, still in its Imperial phase, strangled Labour’s tax policy at birth. It was also deeply, bitterly tribal, demonstrating a kneejerk hostility towards anything Kezia Dugdale says or does; it almost requires a new twitter hashtag: #labourbad.

And no matter how low Scottish Labour slips in the polls, the SNP just can’t help kicking the auld enemy when it’s down. For weeks my inbox has been filling up with press releases accusing them of wanting to punish working Scots while siding with the “Tories” (a noun that must always be spat out rather than spoken) over the anti-Scottish fiscal framework, of which more anon.

It used to be the other way round. As many pointed out on Twitter, 16 years ago it was the SNP promising a “Penny for Scotland” and Labour, then in its Imperial pomp, that heaped scorn on the idea. I covered the 1999 SNP spring conference as a student journalist (I still have a conference agenda signed by one Nicola Sturgeon), and I clearly remember the Nationalists believing it was a game-changer, something that would make an otherwise predictable election come alive.

Of course it wasn’t, just as Ms Dugdale’s move won’t this time round, but the point on both occasions was symbolic rather than substantive: in 1999 Alex Salmond was trying to demonstrate he rather than Donald Dewar truly “stood up for Scotland”, a mantle he later successfully co-opted. Now Scottish Labour, incandescent that the SNP has stolen its battle cry, is attempting to wrestle it back.

It’s also worth remembering the original Penny for Scotland policy was based on the SNP’s belief Scottish voters, being the more caring, left-wing sorts of Civic Scotland mythology, would be prepared to forego the red Tory Gordon Brown’s pre-election tax cut and sacrifice a little more for the greater good. As the subsequent election demonstrated they were not, and thereafter a deep aversion to tax increases entered the party’s DNA.

None more so than Finance Secretary John Swinney, who not only adopts the aesthetic of a fiscally prudent bank manager but often looks affronted at the idea of taxes ever going up. “Oh, the poor folks hate the rich folks,” sang Tom Lehrer, “and the rich folks hate the poor folks,” but while last week’s posturing contrived concern for the lowest-paid workers, as ever Mr Swinney and his party were much more exercised about the rich folks (or rather Middle Scotland), on whom they rely for continuing electoral success.

There was, therefore, something rather unedifying about watching a bunch of (generally) well-paid pundits and lobbyists rounding on Labour at the thought of paying an a few extra pounds a week in tax. Of course the policy isn’t perfect – nor was the SNP’s back in 1999 – but there were lots of people hiding behind practicality when in fact they clearly opposed the principle. Didn’t it occur to anyone that those on the lowest incomes are losing out much more as a consequence of Mr Swinney’s budget cuts than they would through a modest tax rise?

It highlighted how messed up Scottish politics has become, warped beyond logic by grievance, spin, nationalism (of both the small and capital “n” varieties) and a prolonged elevation of style over substance. An SNP spokesman even had the gall to assert that “unlike Labour”, it wouldn’t “shift the burden of Tory austerity onto ordinary people in Scotland”, as if cuts to local government budgets aren’t doing precisely that.

Raising income tax, stormed the SNP, was a “blunt instrument”, not only hammering the poor but potentially scaring off upper earners. But if that’s true of Scotland in the UK, wouldn’t it also be the case under independence? The same tension, as I pointed out in a recent tweet, underpins the Scottish Government’s approach to the fiscal framework negotiations, indignantly trying to cling on to the most comfortable possible UK safety blanket which, it must always be remembered, they ultimately want to cast off.

It was then I got Sturgeoned, with the First Minister replying – to a delighted flurry of retweets – “that’s nonsense, David. With independence we’d get the economic powers to grow econ/population. Under Scotland Bill, we don’t.” Ah, that old referendum chestnut, which usually boils down to tax “incentives” (for which read “cuts”) and a failure to tackle the obvious point that a shared border would render a radically different immigration policy impossible.

Today’s meeting between the Finance Secretary and Chief Secretary to the Treasury Greg Hands, hinges, as usual, on the quixotic “no detriment” principle, although the Scottish Government has cleverly interpreted this to mean greater devolution, and thus divergent policy-making, must never mean Scotland losing out, even though the Smith Commission clearly meant it to apply only at the point of the powers being transferred (it also seems to be forgotten that Mr Swinney agreed to this in the first place).

Of course few are across this sort of highly technical detail, and by kicking up a stink Nicola Sturgeon can demonstrate she’s “standing up for Scotland” ahead of the election, while tenuously casting Labour as siding with the Tories.

“It’s only for a week,” sang Tom Lehrer, “so have no fear”, only in Scotland’s case this tiresome, relentless nonsense will almost certainly last all year.