Donald trump has probably not studied Antonio Gramsci but he doesn’t need to. He intuitively understands the chief insight of that Marxist theorist, who said that power comes from commandeering not only the state, but also the culture. It is not enough to seize the federal bureaucracy; one has to get the tastemakers too. Cue Mr Trump’s arrival this week at Washington’s foremost cultural institution, the John F. Kennedy Centre for the Performing Arts.