The easiest way to differentiate career rabble-rousers from a protest worthy of anyone’s attention is to ask someone in the mob a very simple question: “What specifically needs to change or be promised so that you would be content to go home right now?” For those on the streets of Egypt and Libya this

year the answer was clear. Ditto during the global anti-Iraq war rallies in 2003.

But the increasing numbers of demonstrators “occupying” Wall Street and elsewhere could not answer that question if they tried. Their important message is that “the 99 per cent will no longer tolerate the greed and corruption of the 1 per cent”. Unfortunately, their problem is that the corollary of wonderfully catchy, catch-all slogans is that their ambiguity defies solutions. How should America “redefine how labour is valued”, exactly?