Are the Russians making Sanders win so that Trump doesn’t have to go against Biden?
I would think that to win the election, the Democrats would need to attract some who voted for trump, and Sanders is unlikely to attract them, although Biden might.
I think any American voter who spends so much as a single second worrying about what Putin wants rather than what they want is a fool.
I think that the Russians are interfering in order to sow distrust in the election and in democratic norms, full stop. I doubt they particularly support or oppose Sanders - the disruption is the goal.
Ultimately though, they want Trump. A bumbling idiot that will hurt the nation. And it’s hard to know just how much control they have over him, but it is quite a bit.