Sad to watch this guy.
His big chance was four years ago. He wanted to run.
But, the Big Wigs in the Dem party told him "No." It was time for the First Female President.
Had he run he would have split the Dem vote, and helped elect Trump.

As a good Democrat, he had to play Identity Politics. It didn't matter who would make the better President, he could not stand in the way of the first female President.

There were several interviews with him, two years ago, where he said he would have easily beaten Trump. He is bitter because he chose not to run.

So, he is "hoist on his own petard." Had to play identity politics four years ago, while he was still mentally pretty sharp.
I would like to feel sorry for Joe but he is eating the cake that he himself cooked four years ago.