The democrats are just waiting for a large number of delegates to ‘pledge’ to Hillary.
Then BEFORE the convention, she will be forced to withdraw, and the delegates are freed, and Bernie can’t get them.
Hillary would probably be promised a pardon etc. to make her go along with it. Maybe she’ll cite health issues.
Then the leaders of the Democrat party can select anyone they like to be the Democrat nominee instead.
I think this is how it is going to play out.