Joe Biden did us all a great service several years ago when he came out and said he supported same-sex marriage. Obama was still dithering around and "evolving" at that point, and having Biden come out ahead of him on the issue shamed Obama into finally making the move he needed to make.
I understand that Biden decided not to run for President. But is it too much to hope that either Hillary or Bernie (whoever it is) might put him back on the ticket for another term as vice president?