David Cameron's offer of further devolution for Scotland hasn't been well received by everyone. In today's Scotsman, the former Scottish Secretary Lord Forsyth, one of the Tories' Unionist attack dogs, accuses Cameron of playing into  the SNP's hands. He points out, reasonably enough, that Cameron has undermined Scottish Tory leader Ruth Davidson, who was elected on a promise of no further devolution , and complains that the PM has allowed the debate to shift from independence to "devo max".
"If this is a tactic, it is a tactic that plays into Alex's hands, because the very last thing he wants is people actually talking about what independence would mean," he says.
But Forsyth doesn't confront the danger that denying Scotland greater powers only increases the attractiveness of independence. If Scots conclude that the only way to achieve fiscal autonomy is to vote Yes to secession, the Union may well be doomed.
It's a risk that ConservativeHome's Tim Montgomerie recognises in his persuasive piece  in today's Guardian. He writes:
[T]he UK will be kept together by ensuring that voters normally get the type of government they vote for. Current arrangements are unsustainable. You can't have responsible government in Holyrood when, as now, MSPs control 60% of public expenditure in Scotland but only raise 6% of tax revenues. Devolution that ensures Scotland has to balance its budget is not another step towards independence but a final step towards a sustainable settlement.
He also urges Cameron to take up the mantle of devolution for England. An English Parliament, as I've argued before , is a non-starter - Westminster would never allow the creation of so powerful a counterweight - but the government could introduce ""English votes for English laws", a reform that would amount to the creation of an English Parliament within Westminster. As Montgomerie writes: "The quid pro quo for introducing devo plus north of the border must be English votes for English laws south of the border." Every Conservative manifesto since devolution has included a pledge to introduce this reform, and a government commission  is currently examining the issue.
As Pete Hoskin argues at Coffee House , this is fertile territory for Labour as well as the Tories. The UK is now neither a unitary nor a federal state and its largest constituent group - the English - feels increasingly unrepresented.
But it's not hard to see why Ed Miliband's party remains resistant to English devolution. Deprived of the votes of Scottish and Welsh MPs, a future Labour government could struggle to pass contentious legislation. Alternatively, a future Labour opposition could face what Montgomerie calls a Tory "supermajority". Were non-English MPs excluded from voting on devolved issues, the Tories would currently have a majority of 63 . For this reason, among others, Labour has already denounced  the West Loathian commission as "partisan tinkering with our constitutional fabric".
All of which means the federalist road is Cameron's for the taking.