In what way is Paul Krugman a Keynesian, at all, let alone a “good Keynesian”, David Rapineau? The plain text of the quote from 1997 outright states that the employment level is exclusively the job of the Central Bank. This is so-called New Keynesian neoliberal nonsense, straight up. It’s about as Keynesian as French fries are “French”.
The only reason Krugman ever supported fiscal expansion via deficit spending is because of the fictitious “Zero-Lower-Boundary”, based on the fictitious ‘real interest rate’ malarkey. Krugman is as neoclassical as they come.