There's alway an outcry after a shooting, and people agree "something must be done". Then things quiet down and everybody goes home, and it happens all over again.

But...

I think something's different this time. It's not only hurt black people marching, it's Americans (or British, or French, or the general population of whatever country). And the mayor of DC had it written, in huge yellow letters "Black Lives Matter", and changed the name of a street - just down the road from where the president lives.

I think the scales have tipped.