evidently, the key reasoning strategy of nobel-prize winners is amazingly direct: from any premises whatever, your pet conclusion follows. no matter what the data, it always shows that government should be larger and more active. krugman, i have to say, is merely obsessed: he just desperately wants to be subordinated: he thinks about nothing else day or night: nothing else actually matters.
so as i understand the argument, it's that if you agree that consumption drives the economy, and if you agree that certain governmental activities increase consumption, then you are rationally obliged to agree that such activities should go forward in a slump like this one. er. look: the inference is wildly fallacious. here's a parallel argument: consumption drives economic activity. requiring every american citizen to spend 50% of their savings on amazon this weeekend would increase consumption. so you're rationally obliged etc.
possibly any measures you take will have other effects than sheer stimlation. well assessing those effects - oh, you know, doubling the deficit - might be sort of important i assessing what you want to do.