At the 1968 Democratic National Convention in Chicago, anti-Vietnam War protesters clashed with police officers – whose brutal role in the confrontation was later described by a federal commission as a “police riot” – hijacking the focus of the convention.

Those young demonstrators had come of age seeing continual – and effective – protests during the civil rights movement and national mourning after the assassinations of John F. Kennedy, Robert Kennedy and Martin Luther King jnr, who a year earlier had staked out his opposition to the war.