Gregory Clark reveals all:
Recently a group of economists affiliated with the Cato Institute ran an ad in the New York Times opposing the Obama stimulus plan. As chair of my department I tried to arrange a public debate between one of the signatories and a proponent of fiscal stimulus — thinking that would be a timely and lively session. But the signatory, a fully accredited university macroeconomist, declined the opportunity for public defense of his position on the grounds that "all I know on this issue I got from Greg Mankiw’s blog — I really am not equipped to debate this with anyone."
Clark’s at UC Davis; the only Cato signatory there is Kevin Salyer, who is indeed a fully accredited university macroeconomist — even if he doesn’t feel qualified to debate something as basic as the economics of fiscal stimulus.