All of this tells us four things. First, American society is far from static: it makes no sense to take snapshots of income for just one year. One needs to look at lifetime earnings. Second, the more competition and the more open the market, the better. Closed, stultified, ultra-regulated economies are bad for social mobility. Third, it is rational for normal earners not to back high taxes on the better off: many people who don’t make that much today can rationally hope to end up in the top 10pc or even top 1pc at some point in their careers. Hammering high levels of income is especially bad for those who will only earn a lot very briefly. Last but not least, while these figures are for the US, we can be sure that a similar analysis for the UK would suggest very similar conclusions.