About three-quarters of it appears in this short Wall Street Journal piece:

Mr. Summers, who is widely viewed as a potential Treasury Secretary in the Obama administration, said the economy had deteriorated markedly in recent months and called for "speedy, substantial and sustained" fiscal stimulus. That marked a shift in tone for Mr. Summers. Earlier in the year, he emphasized the need for stimulus to be temporary. This time he said, "we're going to need impetus for the economy for two to three years."

Mr. Summers declined to put a number on the size of stimulus he thought was needed, but noted that some estimates on Wall Street have gone as high as $500 billion to $700 billion. Mr. Rubin seconded his call, saying, "We need very substantial stimulus," though he emphasized the need for a stimulus bill to come along with a plan to reduce the budget deficit over the longer run.

I have little doubt that, if Summers were Treasury secretary, we'd end up with a stimulus package between $500 and $700 billion, which sounds about right to me.

For what it's worth, I disagree with Barron about Summers' job prospects should Hillary get the nod at State. Yes, it would buy Obama some cover from Summers' feminist mau-mau-ers. But it would also make it much harder to appoint a prominent former Clintonite to a top cabinet position. As Ben Smith reports today, there's a lot of anxiety in Obamaland about giving the Clintons such a key role in his administration. "These guys didn't put together a campaign in order to turn the government over to the Clintons," a Democrat close to the Obama campaign tells him. If Obama brought Hillary aboard, then turned around and picked Summers, he could face a small-scale insurrection.  

--Noam Scheiber