Set those questions aside, however, and you have an easy answer for why Sanders gets the brunt of Black Lives Matter activity, at least among Democratic presidential candidates. Unlike his competitors, Sanders is simply the best available vessel for bringing activists’ concerns to the mainstream of the Democratic Party.

The picture might be different if Sanders were more marginal and on the periphery of the nomination fight (like former Virginia Sen. Jim Webb). As it stands, the Vermont senator is the leading alternative to frontrunner Hillary Clinton in the Democratic primary. He earns almost 20 percent or more in most national polls of the race, and is effectively tied for first in New Hampshire. He also dwarfs any other candidate for president—in either party—in terms of shear crowd size: 27,000 in Los Angeles, 28,000 in Portland, Oregon, and 15,000 in Seattle, where his speech was interrupted last week.

At the same time, Sanders doesn’t have the tightly closed-down campaign of Hillary Clinton. He is accessible, as evidenced by the ease with which activists have reached him on stage. And while he’s been clumsy in these incidents, he also hasn’t lashed out. In both cases, he ceded the mic. Compare that to the attempted Black Lives Matter protest at a Clinton rally in New Hampshire. Activists reached the event, but they couldn’t get past security to announce their presence.