As he walked onto the stage during the NAACP’s candidate forum in Detroit last week, former Vice President Joe Biden said, to paraphrase, “You know me. I’m Joe. I was with Barack.”

Biden is relying on his familiarity, as he should: It’s helped him maintain his lead in the crowded Democratic primary field. But his connection to former President Barack Obama won’t be enough to secure the Democratic nomination. In fact, it might hurt him in the long run.