The novelist William Faulkner said: “The past is not dead. It is not even past.” The past 72 hours of burning US cities triggered parallels with 1968 — a year of urban white flight that ended with the election of Richard Nixon. He won on a law-and-order platform that appealed implicitly to white anxiety. Donald Trump does not deal in implicit language. In response to protests in Minneapolis after the police suffocation last week of George Floyd, a 46-year-old black man, Mr Trump tweeted: “When the looting starts, the shooting starts”. The line was used by George Wallace, the segregationist third-party candidate in 1968. Republicans launched the “southern strategy” to win over resentful white Democrats after the civil rights revolution. Mr Trump’s 2016 campaign was the apotheosis of that approach.

But history offers little clue as to whether a sitting president can profit from the same manipulation. The stark brutality of Floyd’s killing — and the fact that his eight-minute suffocation was captured on video — has curbed Mr Trump’s ability to portray the police as victims. He has veered between threats of deploying the military to quell the protests and appeals for calm. Mr Trump’s record suggests he will not be able to resist the temptation to incite. It worked for him once. America’s Black Lives Matter movement took off in Barack Obama’s second term just as Mr Trump was weighing up his presidential bid. “White lives matter” and “Blue lives matter” banners festooned his rallies.

But can he pull off the same feat from the White House? That will depend on how America defines the protests. Wildly different narratives can be built from the harrowing range of video clips over the past few days. Some show white police officers brutally attacking peaceful black and white marchers. Others show cops marching in solidarity with them. Then there are the scenes of looting and burning. Mr Trump claims that most of the Minneapolis protesters are far-left radicals. Anti-Semitic memes claiming that financier George Soros is funding an army of Antifa (anti-fascist) militants have spread. Russian bots have helped disseminate the conspiracy theory. The Trump administration has picked up that thread. In a televised statement Bill Barr, the US attorney-general, said the protests were “planned, organised and driven by anarchic and far-left extremist groups using Antifa-like tactics”. Without evidence, Mr Trump said 80 per cent of the Minneapolis protesters were from out of state. On Sunday, he tweeted that he would designate Antifa as a “terrorist organisation”.