Please correct me if I am wrong, as I have had a limited appetite for conservative "thought", but I do not recall any one making a case for "expansionary austerity" based on the details of ANY known school of economics, even "mainstream economics", flawed and feeble as it is. The whole case was one of conservatives asserting the necessity of doing what the wealthy wanted on political grounds, accompanied by baseless assertions that it would produce recovery, absent any real argument on economic grounds.

I do recall Krugman's columns trumpeting the renewed relevance of Keynes, who was exhumed from the shallow grave in which Friedman and the libertarian think tanks had buried him. But only a tiny minority of economists have even rigorously challenged the "mainstream" of economic orthodoxy, most notably and publicly Steve Keen, Michael Hudson, Jamie Gailbraith and Nouriel Roubini, but also including fund managers such as Paul McCulley, formerly of PIMCO, who had coined the term Minsky Moment in 1998, along with his contemporary advocates.

So far it seems it has been sufficient for the advocates of "mainstream economics" to simply ignore critics and intensify efforts to vilify Keynes based on critiques of Samuelson's synthesis, but not identified as such. Even now Krugman is not so bold as to assert alternative economic approaches or endorse non-mainstream economists. Part of the problem was illustrated by a talk Steve Keen recently gave to a generally sympathetic  audience of British economists, (Keen refers to it as the "George Monbiot Seminar" as Monbiot "got it"), still were unable to accept the role that debt has played in bringing on the current debacle, so strong is the spell cast by their academic training. This is particularly discouraging, as the best critiques for a general audience of the problems with the current approach have been in the Financial Times.

"It is not necessary to have hope in order to persevere."