Read the following items, in order:
1. Clive Crook's column in the Financial Times.
2. Paul Krugman's reply to Crook.
3. Robert Barro's reply to Crook (embedded in this blog post by Crook).
4. Crook's rejoinder to Krugman and Barro.
5. Megan McArdle's comment on the exchange.
Thanks to my friend Peg Kaplan for the link to McArdle, from which I reconstructed the exchange.
