It is a tragic criticism of justice in the US that so many people had expected police officer Darren Wilson to avoid trial. Justice has to be done, but it also needs to be seen to be done and far too many white policemen have killed black US citizens and not paid any penalty for failing to make many in the black community trust the system.

It is an additional sign of this failing trust in the US legal system that the governor of Missouri put so many of his para-military security forces onto the streets ahead of the grand jury’s verdict. He expected trouble and he was not disappointed: Ferguson is burning as yet again the legal system finds a white police officer innocent of any crime despite killing a man. Wilson’s ludicrous defence included the key element of his fear, and his right to act on his fear. He told the grand jury that Michael Brown “had the most intense aggressive face. [He] was like a demon, that’s how angry he looked”. Brown’s facial expressions should not be a reason to kill him.

Barack Obama is America’s first black president, but he has been scrupulous in refusing to make too much of this. Nonetheless, he said in an interview before the verdict that it was clear that there was a lack of trust between communities and law enforcement across the US. After paying the necessary tribute to the difficulties facing law enforcement officers, he also asked the people of Ferguson to remain peaceful in their protests, joining the unanimous chorus of American leadership expecting their legal system to trigger this kind of misery.

It is a real concern that no-one assumed that the grand jury’s verdict was going to be accepted as fair and just. The police seem able to operate outside the law and the judiciary seems ready to defend the police rather than uphold the law. Obama will need to use his federal authority to impose some sense of greater responsibility on local and state governments that they need to work for Americans of all colours.