Remember Thomas Piketty? That Don Quixote of capitalism, the French economist who rode out of Paris in 2013 to assail rising inequality in the western world? The response among the Davos class was to look interested and thenraise vague doubts about his calculations. about his calculations.

But this election season in the US is starting to look like Mr Piketty’s revenge. Inequality in all its guises has become the driving theme for the leading candidates of both parties, and it is confounding the Democratic and Republican establishments. When they hear Beyoncé’s “Formation”, with its strong message about racism in America, it is not that they do not recognise the tune. They do not even recognise it as music.

Inequality always ends up being a problem of indignity, suffered by those on the wrong side of a wealth gap. These indignities can be abstract, like jealousy, or tangible, like the indignities of infrastructure. This is highlighted by the sorry tale of the water supply in Flint, Michigan. Here was a town gouged out by the loss of its industrial base, the lowering of global trade barriers and changes in the car industry. Flint residents are mostly very poor. And for several months between 2014 and 2015, this beaten-down population was supplied with contaminated water due to bad decision-making and plain cheapness from their local and state leaders.