David Torrance: Home Rule wouldn't solve all the Scottish-UK questions

A son of Glasgow, he emigrated with his family to the old colony of Upper Canada as a boy and enjoyed one of those rags-to-riches experiences that often (although certainly not always) followed such a move.

On Saturday evening Scots, Canadians and Canadian-Scots gathered at Glasgow City Chambers to celebrate this bicentenary, although proceedings necessarily skirted over a lively historical debate as to Sir John's true legacy, good or bad.

Speaker after speaker referenced key dates in his career, not least July 1, 1867, when Canada was born as a nation under the British North America Act, the passing of which owed much to the actions of Sir John and the wider confederation movement.

He then became Canada's first Prime Minister, serving in that post (with a five-year hiatus) for the rest of his life. Canadian territory expanded and Sir John bound the nation together via the controversial Canadian Pacific Railway.

As Premier, Sir John enjoyed considerable autonomy under what was later known as Dominion Home Rule, ie the ability to make laws in all matters other than foreign affairs, defence and international trade, all of which remained under the jurisdiction of the Imperial Parliament in London.

While the 1931 Statute of Westminster put an end to those "reserved" powers in most British Dominions (though not in Canada, whose constitution would only be "repatriated" in 1982), the term "Home Rule" still resonates to this day.

Thus the former First Minister Alex Salmond's declaration late last week that Home Rule rather than another referendum (as he repeatedly suggested late last year) was now the SNP's preferred outcome following this May's UK general election.

"Home rule", Mr Salmond explained, "is control of all domestic affairs and taxation. Reserved to Westminster would be foreign affairs and defence. There is massive evidence that's what Scotland wants."

Various opinion polls do indeed show majority support for Home Rule or "devo-max" in Scotland, although one must treat such evidence with care: if that constitutional option is presented as cost-free - and it usually is - then naturally it looks very attractive. But then of course it wouldn't be.

Beyond the simplistic confines of a certain Nationalist mindset, where more autonomy - and of course "full" independence - for Scotland cannot conceivably involve any risk or loss of revenue, there exists that scary, unpredictable place known as the real world, somewhere I dearly wish certain politicians and commentators would spend more time getting to know.

In the real world, as I think we learned during the referendum debate, full autonomy, fiscal or otherwise, isn't really possible. The modern world is typified by a complex inter-relationship between different levels of government, while equally complex fiscal transfers take place both within European Union member states and between them. Sometimes the SNP appears to acknowledge this reality, sometimes - usually rhetorically - it does not.

If, as Mr Salmond et al desire, Westminster granted Scotland Home Rule later this year, it would involve the Scottish budget taking a massive hit on two fronts. First, the Barnett Formula would no longer apply north of the border, which (by the Scottish Government's own figures) would shave several billions off total revenue, while second, the volatility of North Sea oil would no longer be mitigated by the Treasury, resulting in another pretty hefty reduction.

Now of course that could correct itself in the medium to long term, for as the SNP argues it would possess a fuller range of fiscal levers and would thus be able to respond (although quite how realistic that is when pursuing a high-spend, low-tax economic policy is a moot point), while the oil price, as Salmond correctly points out, will likely bounce back at some point, otherwise it wouldn't be "volatile".

But in the short term a Home Rule Scotland would be in a worse position, just as the Irish Free State was after seceding from the UK in the early 1920s. Rather than full independence, it initially enjoyed Dominion Home Rule within the British Empire, with Westminster retaining considerable influence over defence and foreign affairs. Not even Sinn Fein pretended Ireland was better off financially as a result.

Of course the SNP would not be content with Home Rule even were it to be granted, how could they be when the future of Trident and the ability to declare "illegal wars" remained in the hands of the Imperial Parliament? Rather it would grant, as Michael Collins said of the Anglo-Irish Treaty, "freedom, not the ultimate freedom that all nations desire and develop to, but the freedom to achieve it".

Nationalists are more consistent on this point than some opponents give them credit for. Since the 2001 UK general election, when the current Finance Secretary John Swinney was in charge, the SNP has essentially pursued a twin-track constitutional strategy, advocating both independence and, failing that, "fiscal autonomy" (yet another term for Home Rule). Following defeat in last year's referendum it was always likely the party would revert to the lesser option.

Indeed, within weeks of the referendum Nicola Sturgeon (not yet First Minister) put her name to the Scottish Government's submission to the cross-party Smith Commission, which basically restated its definition of "devo-max" as first outlined during the "National Conversation" during its first term in office, calling for "maximum self-government" as a consequence of Smith.

Of course Smith didn't recommend that, and thus Mr Salmond and his colleagues continue to rewrite history by claiming that Unionists have reneged on "The Vow", which promised "extensive new powers" rather than Home Rule. That said, the new First Minister seems to have forgotten all about a speech she delivered in late 2012 declaring the UK's "ability to re-invent itself" as "spent". Yet later this month the UK Government will publish draft clauses in an attempt to do precisely that.

Whether it succeeds is worthy of cynicism, for I've long argued only a federal settlement could properly re-invent the UK politically and constitutionally. Reactive, piecemeal devolution is subject to the law of diminishing returns, while a post-colonial style "Charter of Autonomy" for Scotland (an option Scottish Secretary Alistair Carmichael recently promised to "explore") would likely become another tool in the Nationalist armoury.

A hundred and fifty years ago Sir John MacDonald had no doubt as to his constitutional vision, hoping the UK and Canada would have "a healthy and cordial alliance". "Instead of looking upon us as a merely dependent colony," he added, "England will have in us a friendly nation." But then Home Rule in a 21st-century context certainly would not achieve that between Scotland and the rest of the UK.