Charles M. Blow: Joe Biden is still problematic on racial issues

All five of these things are simultaneously true:Joe Biden is the Democratic front-runner and may well be the nominee.He is by far the favorite candidate among black voters.He was a loyal vice president to Barack Obama, and the two men seem to have shared a deep and true friendship.He, like the other Democratic candidates, would be a vast improvement over Donald Trump.And, Biden’s positioning on racial issues has been problematic.This issue exposed itself again Thursday during the presiden