LAST weekend’s Sunday Herald led on a “furious row” brewing between Richard Leonard and Jeremy Corbyn. If true, it has interesting implications for the independence movement, because, while both leaders have until now remained silent on Britain’s constitutional future, the reported quarrel concerns Leonard’s proposals for a “radical” shake up of UK parliamentary democracy.

Serious new constitutional thinking in Labour would be a great thing for Scottish politics. And I don’t doubt that Leonard genuinely wishes to make radical proposals, if only to halt a slide towards independence. But, even if his run-in with Corbyn is real, I doubt it can amount to much. Britain, in my view, has largely exhausted its potential for democratic reform, and any new proposals can only involve rejigging and rebranding existing arrangements.

Of course, we’ve been here before. Leonard isn’t the first Scottish Labour leader to agitate for reform. Johann Lamont famously quit over interference from London, while her successor, Kezia Dugdale, announced plans for what she called (to great derision) “a new act of Union”.

This badly-botched branding essentially killed off Dugdale’s proposals and, with them, any discussion of the merits of federalism. Since then, for roughly two years, both sides have retreated into tribal comfort zones. And that’s a shame, because the pro-independence part of Scotland lost a useful opportunity to have a level-headed debate about the nature and limitations of the British state.

For many people, simply invoking the word federalism is enough to sound radical. And, in one sense, it surely is, because Scottish political life has been so badly disturbed by tribalism that any attempt to define a middle ground is a bold move. Radical? Perhaps. Brave? Definitely.

But what does it actually mean, and would it truly work in a UK context? These questions have barely been confronted. Federalism, at this stage, is little more than a word, and, while uttering it involves an admirable level of political bravado, words alone cannot solve a crisis of British proportions.

The biggest problem in any idea of federalism is what happens to England. In population terms, Britain’s largest nation dwarfs the others. London alone is far more significant to Britain’s political economy than Wales and Scotland combined. But while London and its hinterland gets preferential treatment for obvious reasons, and while the other nations get a parliament to lobby for them, the rest of England has been shut out and ignored. This is the toxic breeding ground for Ukip and racist politics.

Theoretically – somehow – federalism would need to involve an idea of equal powers shared by four unequal agents: Northern Ireland, Wales, Scotland and England. A federal body would retain control over foreign affairs, defence, currency, welfare and pensions.

Realistically, the only viable model would be regional assemblies across England to prevent an English parliament overshadowing the rest. However, English regionalism has never gained much traction, largely because people don’t feel any attachment to amorphous ideas like “North West England”. An all-England parliament, aside from crowding out the other nations, would also be dominated by London’s concerns. Perhaps the best model might be a “non-London England” body, but this would have even less natural sense of identity than a more regionally subdivided model.

So where does that leave us? This is the first question for any UK federalist. Not coincidentally, it’s the question that all proposals for federalism tend to ignore.

Scotland’s parliament has allowed the country to restore a sense of identity. It has also permitted a certain degree of policy autonomy over issues like free school meals and higher education.

On the downside, despite overwhelming centre-left majorities in the parliament, Scotland was still landed with the worst of neoliberal policymaking. Private finance initiatives have become a national embarrassment. The incomes of the richest one per cent also skyrocketed under the first decade of devolution. And devolution may have been part of that neoliberal story, since it involved passing responsibility away from central governments and down to lower tiers.

Worst of all, devolution has left Scotland with no voice when it really counts. I have openly expressed my doubts about Holyrood’s uncritical attitude to the European Union. But there’s a wider story to the Brexit debacle. Despite an overwhelming consensus in Scotland, the UK Government simply hasn’t listened to Holyrood on any serious geopolitical issue, from bombing raids on Syria to Trump and Brexit. Ultimately, these are the big issues that determine our fate, and on them, Scotland has been told to mind its own business. Would “regional England” fare any better? I highly doubt it. Indeed, more devolution would probably help Westminster play “divide and conquer”.

A breakup of Britain remains the most serious prospect for resolving differences and restoring good working relationships. Putting the pieces back together is simply too difficult. The case for independence has flaws. But that case has been subjected to advanced interrogation techniques with a level of intensity last seen in Guantanamo Bay.

By contrast, Brexit managed to sneak through without even a minimal economic plan. Federalism, likewise, has undergone only the lightest of grillings.

That doesn’t mean I disagree with Leonard on everything. It’s great that he wants to abolish the House of Lords through a process of constitutional “reform”. But you can’t reform away the arms trade, the secret state, the City of London, and all the faded imperial glories that make Britain what it is today. You can’t reform the monarchy – not in this lifetime. And you can’t reform the intrinsic inequality between Britain’s units of nationality. Whether you call it a “new act of union” or something else, plans for federalism are doomed either to fall flat or, worse, to fuel opponents of genuine change.