[WS:] Did you check my analysis of government spending I posted to the list today? If not, please do so. It shows (using BEA data) that there has been very little difference in the level of government spending between the two parties. There might be some minor partisan differences in how the money was spent, but overall differences seem rather trivial.
I agree with you that individual industries or even companies may see big differences in which party gets elected - but this has more to do with political patronage than with the keynesian policy.
If I read Krugman correctly, most of Obama's "stimulus spending" constituted of tax cuts and bailouts instead of purchases of goods and services, which predictably had minimal effect on employment. I do not think that a Republican administration would do anything substantially different - except perhaps redistributing these bailouts and tax cuts differently - so your 12% "counterfactual" does not look very convincing. In other words, different crowds would lose their jobs under republican administration than under Obama, but an the aggregate level it would still be about the same.
Wojtek