For #BlackLivesMatter, targeting Bernie Sanders isn’t just about 2016. It's about today.

When Bernie Sanders held a rally at the University of Houston on Sunday, he mentioned Sandra Bland by name — a victory for #BlackLivesMatter activists who've made a cause of Bland's mysterious death in a Texas jail cell.

From the perspective of the national political media, this was the resolution of a drama that had erupted over the weekend — when Sanders was challenged at the progressive conference Netroots Nation to integrate the deaths of young black men and women at the hands of police into his campaign.

But from another perspective, it was just another step in calling attention to Bland's case — and getting white Americans, progressive or not, to pay more attention to the value of black life. After all, the #BlackLivesMatter movement is putting more effort into Bland's case, and other individual cases of African Americans killed by police or who died in custody, than it is into targeting Sanders or other candidates.

To understand why #BlackLivesMatter activists challenged progressive presidential candidates over the weekend, you have to understand that they're working on both levels. They're using national political organizing to call attention to, and reinforce, the immediate work being done in individual cases....