The appalling racial injustice inherent in the Trayvon Martin tragedy reminds us that there is still much to do.

We can stop being so taken aback by Black Lives Matter. If we didn't need to be reminded, there would be justice for Breonna Taylor, a Kentuckian like me, and countless others.

Caste is about dividing people up in ways that preclude every form of solidarity, because even in the lowest castes, there are divisions and sub-castes, and everyone's co-opted into the business of this hierarchical, silo-ised society.

Boycotts have been a critical part of social justice in American history, particularly for African-Americans.

Private landlords as well as public landlords are free to discriminate against people with criminal records for the rest of their lives. You come out of prison, and where are you expected to go?

In Western Australia, minerals are being dug up from Aboriginal land and shipped to China for a profit of a billion dollars a week. In this, the richest, 'booming' state, the prisons bulge with stricken Aboriginal people, including juveniles whose mothers stand at the prison gates, pleading for their release. The incarceration of black Australians here is eight times that of black South Africans during the last decade of apartheid.