Biden is a lying, incompetent buffoon.
.....oh wait, I just described easily 75-80% of politicians in Washington. I guess he fits right in, but you're right, he's definitely dumber than most.
How a guy like that gets to be VP, I'll never understand, but playing the political game has always had little to do with actual intelligence and competence, and a lot to do with shrewdness and opportunism and playing on people's emotions.