Read this essay (http://www.econ.aueb.gr/en/uploadfiles/AllRP092012.pdf) about the theory of expansionary fiscal contraction. In a nutshell the theory proposes that austerity (fiscal contraction) can lead to economic growth as consumers might anticipate smaller taxes tomorrow, and hence increase their spending today, thus boosting the economy. It also proposes that austerity would reduce the effects of crowding out, but this point is only really relevant when the economy is at full-employment, and so can be ignored regarding the current situation we are in.

The introduction of the essay is extremely good at explaining this point.

UPDATE: A follow-up of this issue is available to read here.