I was fascinated to learn of Cassidy and Layard, and the risibly weak argument they present which seems to be fashionable now on the left, and thought other Freepers might be, too. Wilkinson counters them dispositively.
The standard for being "poor" keeps rising. Take today's "poor" person and put them up against a 1920s "middle class" person, and tell me who has the better standard of living.
The Left needs to constantly redifine poverty upwards in order to maintain a constituency of "poor" victims to vote for them. They need lots of class envy, too.