A defence of austerity

Is there anything to be said in defence of the coalition's fiscal austerity? Martin Wolf and Jonathan Portes think not. And the Tories' usual defences of their policy seem inadequate. The idea of expansionary fiscal contraction has come as close to being refuted as any macroeconomic idea can be - at least in terms of its relevance here and now. The government's claim to be "fiscal conservatives and monetary activists" is undermined by Osborne's failure to change the inflation target. And the idea that austerity is necessary to retain the faith of bond markets is, at best, an unproveable counterfactual and at worst ("we could have been like Greece") mindless drivel.
So, what can be said for austerity? If I were a Tory, I'd try the following.

The focus of policy should be upon long-term prosperity, not the here and now.
One reason for saying this is that complaints about current high unemployment are mere crocodile tears. If Labour really were concerned about the costs of short-term downturns, it would have used its 13 years in power to improve risk-pooling - either by increasing out-of-work benefits or by encouraging the development of macro markets. It didn't do so, and voters didn't want them to. This tells us that the public behave like Lucasians (pdf), in thinking that the costs of downturns are small.
What's more, the very fact that real bond yields are low tells us that future income is very valuable, relative to present income. We should therefore try to maximize it. And austerity raises long-term growth.
This is partly because there can be a trade-off between stabilization policy and longer-term growth. One overlooked reason for this is that a counter-cyclical fiscal expansion would merely involve spending on unproductive boondoggles that burden future generations. As Britmouse says: "I doubt the Pembury road will ever get priority over the expensive white elephants."
More importantly, though, there's some evidence - not as much as Amity Shlaes pretends, but some - that lower government (pdf) spending can raise long-term growth. Granted, that evidence comes mainly from cross-country research of questionable validity. But two mechanisms make the link plausible.
One is Baumol's cost disease. Government, by its very nature, has low productivity growth. This means that having a big government condemns us to low growth by simple maths. Worse still, the rising relative cost of government over time will crowd out the private sector - and the bigger government is, the sooner it will do so.
The other is that, in the long-run, social norms matter. The persistence of big government threatens to create a norm in which young people to look for safe public sector jobs in sclerotic hierarchies, which would divert talent away from the private sector towards low-productivity-growth work. This could choke off future growth. Also, prolonged austerity now is creating low or negative real interest rates. This will encourage youngsters in future to take on more debt - because macroeconomic conditions in our formative years shape our behaviour (pdf) throughout our lifetime. In this sense, austerity today will encourage borrowing in future - maybe for consumption but maybe too to set up businesses. This too should raise future growth.
As for why we should cut now, there are two reasons. One is that it's what the public want: Labour's offer of (slightly) smaller and later spending restraint was rejected by the voters.The other is that the sooner we start cutting, the easier it will be in future - partly because the objections will be out of the way, and partly because once we get into habits, it's easier to stick to them.

Now, I suspect this sort of argument makes more sense than the standard Tory ones - though that's a low bar. As for how much sense it makes, I'm not sure.