HRC calling in the favors. Setting up a brokered convention.
This may be the future for the Dems, though. I notice that most European countries seem to have a multitude of fractional parties that form government through shifting coalitions. The Democrat Party appears to have achieved that condition within itself in America.
There is no “center” to the Democrat wheel. As it spins, it is blowing apart.
My thought also. Hillary wants to take the easy way to get the nomination. And Sestak helps her and at the same time gets some name recognition and money.