Further to Eliot Spitzer, I agree in principle with the surprising editorial in the Wall Street Journal this morning, arguing that Client 9 should be treated on a par with Clients 1 to 8. The Journal is no fan of Mr Spitzer, and neither am I, but it is correct to say that, now he has resigned, state-backed vengeance is inappropriate.

Not being a US legal expert, I don’t know whether he broke federal prostitution laws by paying for “Kristen” to take a train down to Washington, or money laundering regulations by “structuring” his payments to avoid tax or scrutiny.

But it is fairly clear that Mr Spitzer was not laundering money - he was simply trying to hide his use of the Emperors Club. So it is not obvious why he should now be treated any differently from the others. He is plainly suffering quite a lot anyway.

In my Financial Times column this week, I return to the compelling topic of Eliot Spitzer. I have nothing here to say about prostitution; instead, I argue that crusading populists rarely achieve what they promise in office. You can read it here and please comment below.