For Laclau-Mouffe, the problem for revolutionaries is still capitalism (although more widely defined to include socio-political aspects more than simply economic ones). Therefore they still see material conditions as the problem. They are still Post-Marxists. What they argue is that we need to go beyond the working class essentialism which has been a problem that the left has struggled with, and which seems especially problematic since the advent of neo-liberalism which has seen a break up in the traditional working class power bases. Instead they see the progressive force arising out of particular interests (identity politics, working class struggles etc) to discursively construct a new universality. Mouffe-Laclau are still committed to (an thus far more 'orthodox' than many other Post-Marxists) a notion of Hegemony. It is simply that this will be constructed through 'an empty universal', which will be filled with varied and intersecting particulars rather than created by a working class that seeks to come to represent other particulars. This comes from their reading of Gramsci, in which they see that through the construction of hegemony, all interests are transformed beyond their particularity. In short, there is no universal that we simply have to roll out when the time comes and get everyone behind it, but the universal itself must be constructed. It is not, therefore that there are not material issues that confront society, but that there are no a priori universals that can be simply set in motion at the right time. Thanks for the link though, does sound useful. If anyone is interested in this kind of stuff, Laclau, Butler and Zizek wrote an awesome book debating each others conceptions of this kind of thing called 'Contingency, Hegemony, Universality: Contmeporary Dialogues on the Left'. Worth a read.