End of the line for the lockstep hokey-cokey
So farewell then, the lockstep. It has gone the way of the the legislative competence order into the great policy cloud in the sky.
For those not familiar with the lockstep, I draw your attention to the excellent BBC dictionary of devolution. Here's a reminder of the trouble it caused in Welsh Conservative ranks.
The UK government originally said it was being introduced for two reasons: to ensure parity with Scotland and because "progressivity" should be reserved to Westminster.
In the wake of the Scottish referendum, Stephen Crabb has now dropped those arguments.
This is what he told the conference about the income tax powers today: "I have always believed that those powers should be far-reaching and flexible, and I am committed to removing obstacles to them being used effectively - which is why tomorrow I will be asking my colleagues for their agreement to amend the Wales Bill - to remove the lock-step restriction on how those income tax powers are used."
He added, slightly ambitiously: "Our tax devolution will end the politics of the begging bowl in Wales."
As if that were not exciting enough for constitutional anoraks, he also announced a commitment to the reserved powers model (check your dictionary again) if the Conservatives win the general election.
"I will be asking my department right now to begin work on a draft template for a reserved powers model of devolution for Wales that will stand the test of time and end the absurdity of devolution questions being settled by lawyers in London rather than by the people of Wales and their elected representatives."
There's now a cross-party consensus behind the reserved powers idea; there's less of a consensus on which powers should be reserved to Westminster and which should be devolved to Wales.
The removal of the lockstep should usher in a new style of political debate, with the merits and de-merits of different tax regimes discussed (as they tend to be outside Wales).
But for all Mr Crabb's talk of "a new era of responsible government in Wales" the reality is that the tax-varying powers won't kick in unless the Welsh government triggers a referendum it shows little sign of wanting to call.