Instead he has this weird post that seems to take the view that Krugman doesn't understand, respect, or agree with a forty year old revolution incorporating expectations into macro.
This is simply bizarre because Krugman actually works in that tradition, and that has formed the bedrock of what he's had to say on monetary and fiscal policy in a liquidity trap.
We all know what Krugman means when he talks about saltwater/freshwater. He's talking about weird resurgences of the Treasury View among people like Fama (they actually do say that stuff). He's talking about claims that the problem is not an aggregate demand problem from people like Casey Mulligan.
He's not talking about expectations in macroeconomics.
What's sad is that Williamson is a sharp guy and very accessible as a blogger. He could offer an interesting counter-arguent to Krugman, but he chooses to post weird stuff like this. I don't know why.