Putting aside his genuine commitment to it, Clegg is facing two ways with this announcement: the public and his own party. The message for the former is that the cuts won't leave the poorest behind. For the latter, it's more a massage in the wake of the struggle over tuition fees. This is, after all, a distinctively Liberal Democrat triumph – and a welcome one at that.
It's testament to the difficulty of the spending review that policies like this will not be enough to win the argument over fairness. No longer does "investment" in the poor count as "fair" by default – and rightly so. Rather, questions abound. Who loses out? What about the middle classes? What is the government's definition of "fair"? And so on. Nick Clegg dealt with these quite well during his interview on Today earlier – and he partially did so by shifting the coalition's emphasis on tax. Until now, the raised personal allowance has been sold as a measure for the least well-off, even though it benefits better-off taxpayers as well. Here, Clegg stressed instead that it is effectively a tax cut for "everybody". Looks like he wants to sweeten the pill for the the middle classes too.