Another possibility at the convention... Candidates combine delegates to make a ticket [View all]
"In 2020, there will be 4,750 delegates: 3,979 pledged delegates and 771 automatic delegatesmore commonly known as superdelegates.[1]" https://ballotpedia.org/Democratic_delegate_rules,_2020
Magic number is 1990
If the numbers look like this, no one has reached the magic number.
Sanders 1500
Buttigieg 850
Biden 750
Bloomberg 600
Others 279
Then Super Delegates come into play and the new magic number is 2375. Leave aside the possibility of Biden wanting to be VP a second time. I doubt that will happen. The fun really starts. If Buttigieg and Biden team up, they are at 1600 and need almost all of the Super Delegates. (This scenario makes the "Democratic Establishment" attacks a particularly dumb move.) Sanders and Warren team up and they get to around 1650 (which is looking more far fetched by the day).
The point is that if the candidates team up at the convention, they can assemble a winning coalition. It's not Sanders or Biden or Buttigieg against the world at that point. It could be Biden/Buttigieg, with Klobuchar as Secretary of Something.
The opposite can also happen. Sanders wins almost everything going into and out of Super Tuesday. Then the primary will be conventional. It will be like Kerry '04.
Just something to add to the long list of things to think about.