Here is the Obama Goal: ELECT A DEMOCRAT IN 2016.
Here are the only viable options (that we know of):
Hillary
Bernie
Joe
At this point Obama doesn't know what Joe will do or even if he could win. He probably does realize that Bernie cannot win. If Joe declines he has to go all-in for Hillary - mild slap on the hand and no indictment. If Joe is in then it's thumbs down on Hillary just enough to get her out of the race with minimum damage to his party.
There are states with Primary ballot filing deadlines starting in early November so time is running out on Joe to make his decision. This has to come to a head within the next month or so.
You forgot one very viable alternative, in fact the only one that can hold together and even build on the Obama coalition that elected him two times and will absolutely not dismantle the Obama “legacy” .....MICHELLE
those primary deadlines are irrelevant to Democrats and can and will be changed or ignored if necessary to attain whatever results are deemed most appropriate up to the day before Primary day.
No doubt in my mind, Joe is IN.