There is a garble in the arithmetical example at the end of the fifth paragraph of my post on foreign aid. $23,000 - $2,000 = $1,000 should be $23,000 - $20,000 - $2,000 = $1,000. That is, when the welfare recipient's income rises from $20,000 to $23,000, he gains $3,000, but loses $2,000 because he is no longer eligible for the welfare benefit of $2,000. This leaves him with only $1,000 net from $3,000 in additional earnings, yielding a marginal tax rate of 67 percent.
Sorry for the mistake.