"Paul Krugman is now reduced to making fun of my name."
Evidently he believes the term "cockroach ideas" was inspired by the first syllable of his surname. This seems unlikely. Krugman has been writing about cockroach ideas for years. Here's an early example, from March 2011:
Way back, when I spent a year in the government, an old hand told me that fighting bad ideas is like flushing cockroaches down the toilet; they just come right back. I’m having that feeling a lot lately, on at least two fronts.
One is the crowding out issue. I keep encountering both the same old misunderstanding of Ricardian equivalence, and people citing evidence from periods when the economy was nowhere near the zero lower bound. The latter was, perhaps, excusable when the idea of a liquidity trap was still new; but folks, we’ve been at the ZLB for two and a half years now:
The other is the whole “the Social Security trust fund doesn’t exist” thing. I’ll just repeat what I said back when Bush was trying to push through privatization:
Social Security is a government program supported by a dedicated tax, like highway maintenance. Now you can say that assigning a particular tax to a particular program is merely a fiction, but in fact such assignments have both legal and political force. If Ronald Reagan had said, back in the 1980s, “Let’s increase a regressive tax that falls mainly on the working class, while cutting taxes that fall mainly on much richer people,” he would have faced a political firestorm. But because the increase in the regressive payroll tax was recommended by the Greenspan Commission to support Social Security, it was politically in a different box – you might even call it a lockbox – from Reagan’s tax cuts.