On Sept 9, 2010 David Cornelius Smith, 28, an unarmed black man, died face down on a YMCA basketball court in Minneapolis as a white officer knelt on him for four minutes. Police had been called because Mr Smith was "throwing a basketball aggressively”. No criminal charges were brought, and the officer was not disciplined. No one on the court had a smartphone and there was little coverage of the incident, even locally. America has not heard the name of David Cornelius Smith. A decade later, two miles away, and in remarkably similar circumstances – they both suffocated – George Floyd, an unarmed black man, died on a street corner beneath the knee of Derek Chauvin, a white officer. Bystanders filmed it, and America erupted in protest. But, shocking as it was, Mr Floyd's death was no isolated case.