Does Obama have a responsibility to address race riots in major metropolitan areas? And if so what should he say?
Do you even watch TV news? I am not sure what it is like on America, but the Prime minister... I can't ever once remember talking about any specific crime, unless maybe it was a bill inspired by a particular case, but even thinking on it I can only remember provicial politians doing things like that.
I think when some terror suspects were arrested in Toronto the PM might have said something.
I think your term "race riots" is part of the problem here. I think what is going on in London - that's riots. We had a riot in Vancouver this year as well, but are what you are talking about riots? Are storefronts being burnt down? Are people looting?
I think the president would comment if that were the case, unless it is so widespread it is like incidences of cats getting hit by cars, but if that is the case, well, wow. I don't know where you get the idea that politicians can cover up stories - if the media wants to talk about things - then politicians will answer.
They can't help it. It is possible to avoid minor issues, but if the media wants blood on a story, they will get it; they can't avoid it. Most politicians will comment just to manage the message.