Hmm. Something seems off here. Did this super-rich hundredth-of-the-1% in the ’50s really a) pay anything near those super-high 91% marginal rates, or did they b) employ accountants and loopholes to avoid them (as the conventional tax-reformer wisdom would have it)? If you read Krugman’s paragraph you’d probably conclude (a)–high income tax rates really sock it to the rich! But the truth is closer to (b).

According to this CRS study, that 91% marginal rate produced an effective income tax rate on the top o.o1 percent of only about 45%. Krugman himself appears to be relying on Piketty and Saez–but they come in with an even lower figure, 31%. They only get to 70% by including corporate taxes, which Krugman mentions, and estate taxes–which he doesn’t mention at all.