One defense of the too-small stimulus is that it would have been impossible to get a bigger one through Congress. Atrios points out a bigger stimulus wasn’t even on the table:
The memo to Obama, however, detailed only two packages: a five-hundred-and-fifty-billion-dollar stimulus and an eight-hundred-and-ninety-billion-dollar stimulus. Summers did not include Romer’s $1.2-trillion projection. The memo argued that the stimulus should not be used to fill the entire output gap; rather, it was “an insurance package against catastrophic failure.” At the meeting, according to one participant, “there was no serious discussion to going above a trillion dollars.”
Why would Summers exclude the larger plan from consideration, given that Romer and Krugman and lots of other knowledgeable people wanted it?