It's almost a quarter of a century since Alex Salmond (in)famously interrupted monetarist Tory Nigel Lawson's Budget speech, branding it an "obscenity" when Margaret Thatcher's chancellor announced a reduction in the rate of corporation tax to a paltry 25%. Mr Salmond was suspended from the House of Commons for his troubles.
Of course, the realpolitik of government means that Scotland's now first minister has long abandoned such crude moral posturing, and a now long-standing demand of Mr Salmond is the devolution of corporation tax powers to Scotland, which would enable Holyrood to reduce the rate to a positively neoliberal half that which so exercised him when he was something of a radical firebrand.
So big companies and their shareholders would get richer, while a reduction in tax revenues would hurt hard-pressed public services and thus Scotland's most vulnerable?
Of course not - the Reaganomics of the Laffer curve demonstrate that reducing taxation rates can so stimulate economic activity that total tax revenues increase, so it's win-win.
Well many would dispute that this theory actually works in practice, but of course the Scotsman has provided a nice empirical example in the last couple of days, in the shape of Amazon's significant investment in Scotland. So the SNP slips Amazon £10 million or so in government grants, the global behemoth builds a shiny new "fulfilment centre" in Dunfermline and naturally the public coffers are bulging with all that additional corporation tax revenue?
Er, nae quite, because Amazon.co.uk is based in Luxembourg, so even though I buy something from Amazon and it comes up the M90 from darkest Fife to the sunlit uplands of Dundee I've actually bought it from a company in an overseas tax haven.
But naturally all this is HMRC/the Westminster Government's fault, since corporation tax powers are still reserved and thus the SNP Government has no say in the matter.
Oh aye, so Amazon invests in the UK on the basis of an effective zero per cent corporation tax rate and a grant from the Scottish Government, and the Scottish Government would do what precisely if powers over corporation tax were devolved? Raise the effective rate of corporation tax by closing the loophole?
Seems pretty unlikely. Which is presumably why Alex Salmond is refusing to say precisely how a company like Amazon would be treated with devolved corporation tax powers or in an independent Scotland.
Thus a de facto zero per cent corporation tax rate is taking the Laffer curve to extremes, but in Amazon's case reducing the rate has certainly attracted inward investment. However, this hasn't really done much for tax revenues. In fact in simple terms the public purse has suffered in two regards, since corporation tax revenues have disappeared courtesy of the loophole and then there's the government grant paid to Amazon for investing in Scotland in the first place.
Of course, it's true to say that it's not just about corporation tax per se, but that the workers employed by Amazon will pay more tax, the inward investment will result in other economic spin-offs, blah, blah.
Which is all very well, but obviously very difficult to quantify.
However, with tax avoidance schemes by big corporations being an ongoing bone of contention at Westminster, and in view of the SNP's desire to have these things decided by Holyrood, it's surely incumbent on Alex Salmond to tell us precisely how these matters would be dealt with.
Otherwise this all looks like another example of SNP posturing against Westminster which when examined doesn't really stack up and leaves all sorts of awkward questions unanswered.
Of course, as with the more general point about how the Nationalists would wave some kind of magic wand and "grow Scotland's economy" if only Holyrood controlled more economic powers, the grievances and soundbites are easy, but explaining how precisely these things would work in practice is a more difficult matter entirely.
So as with other vexed economic issues like the currency, interest rates and public borrowing, when the issue of corporation tax is put under the microscope the SNP seems unable to explain precisely what they would do with such powers. Perhaps it's about time we were telt.