Must-Read: I have only one critique of Justin Wolfers's series of tweets here. He says that they are simple math errors. It is true that they are conceptually simple. But getting all this right is not easy--I have seen Alan Blinder get it wrong (in the context of a $12B surge in inventories in a single quarter, and its effect on real GDP growth rates) at a blackboard in his OEOB office during the Clinton administration.
This does explain a puzzle. As somebody-or-other said in the conversation, if you believe with Gerry Friedman that all of the shortfall in real spending growth since 2007 can be easily recaptured via demand channels alone, then Sanders's proposals are at most one-third the size that they should be--and that is the critique that Friedman should be making of Sanders given Friedman's beliefs about aggregate supply. (Since I do not share those beliefs, I think Sanders's fiscal stimulus proposals are about right-sized):
On Twitter: "Romer and Romer find what look like...: