If we are ever to secure our freedoms political power has to be devolved. Recognition of this imperative immediately begs the question of which powers should be devolved and to whom. Perhaps even more important is how ordinary people can ensure that these powers are not returned to central government against their will. Inevitably governments, no matter which shade of political opinion they represent, will try to centralise power.
One of the beauties of a federal system of government is the way it reduces creeping centralisation by reserving certain policy areas to lower levels of government. Then if freedom is attacked, people can vote with their feet and move elsewhere.
While it's true to say that mission creep has affected even federations like the US, from a UK perspective, a federation looks like a pretty good way to keep power a bit closer to the individual. Certainly it's possible to imagine the UK as a federal state with an English Parliament sitting alongside the devolved administration in Edinburgh and a beefed-up assembly in Wales. But in terms of the subject of this posting the multinational federation solution would largely fail to disperse power in a meaningful way - the English administration would control power over pretty much everything that affects people's daily lives in the same way that the UK government does today. In essence government would remain a top-down affair with behaviour and choices defined for us by an overweening state.
If power is to be devolved and to stay devolved, the Constitution needs to pass power not to national governments but to lower administrative levels. In England this might be the county. Or then again, why not disperse power still further - perhaps to the level of the community? Or even (perish the thought) to individuals.
Whatever level is chosen, power would reside there, but could be passed upwards if the voters so decided. So a community might decide that it wanted to pass power over its school up to county level so as to pool resources and seek economies of scale. Later, if it was dissatisfied with the county administration, it could simply take the power back. Then again, if it wanted to pass control of its school over to a private sector administrator (who might offer similar incentives driven by its own economies of scale) it would be perfectly free to do so.
In order for a system like this to work the tax raising power would have to reside at the lowest level of government. In this way the community in the example above would simply pass on to the county (or the private sector), a mutually agreed level of funding to support the supply of services. It would pass on funds to central government for defence and foreign relations in the same way.
The critical question that needs to be answered by those on the left is: are you willing to forgo giving to central government the power to redistribute between regions. If that power is given to away then devolution becomes a sham and we are left with a shuffling of the deckchairs. Central government can demand what it likes because it holds the purse strings.
A radically devolved model of government will only work if there is a direct relationship between the votes cast and their financial consequences. In essence you can have liberty or you can have redistribution but you can't have both.