Church massacre shows the US must do more to ensure justice for all races

When the social volcanoes of gun violence and race hate erupt simultaneously in the United States, as they did when a young white man shot dead nine blacks in a church in Charleston, South Carolina, last week, Americans look to the president for moral leadership. Barack Obama captured the sentiment of revulsion and support for gun controls when he refused to "act as if this is the new normal".

The political will to introduce controls has long been frustrated by the powerful lobby of the National Rifle Association. It took the massacre of 20 schoolchildren in Newtown, Connecticut, two-and-a-half years ago to spur Congress to vote on background checks for gun buyers. The measure was narrowly defeated but has not lost momentum, with six states going it alone with a similar law. Sadly, the US seems unlikely to ever have stringent gun laws. But there should at least be controls on assault weapons and online sales.

Obama will also be remembered for his understatement after the exoneration of a white police officer over the shooting of an unarmed black man sparked nationwide riots - that the nation still had work to do on race relations.

This week he confronted the issue head-on, saying it was not just a matter of it not being polite to say "nigger" publicly - America's legacy of slavery "casts a shadow that is still part of our DNA".

Still, it would be unfair to say the US has made no progress at all on race relations. The respected Pew Research Centre in Washington has found that blacks under 40 are less likely to believe racism is an obstacle to advancement. Mistrust is increasingly focused on the police and the institution citizens should trust the most - the courts. That is not surprising when blacks are so over-represented in jails. The perception that racism pervades and perverts justice needs to be addressed to break a generational cycle of alienation and safeguard social harmony and cohesion.