If Obama wanted to endorse Biden, he would have urged him to run in 2016, and he didn't. His refusal now says everything.
Biden is headed one way, right to 1-2% before Iowa.
The clown car is choreographed by Clinton, and serves as a dilution service against what she perceives is her primary threat, Sanders. Think about it, do you think Castro and Booker are really that concerned about trans anything. They have to take a piece of the fruitcake pie and carve it out away from Sanders. That's all they are doing, and they are doing it for Clinton, not themselves. These men are smarter than that.
There is a bigger drama here, and I do not understand why no one sees it. Clinton is Joan of Arc come September, and 10-12 of these fruitcakes are in on the drama.