Obama led the Democrats to political disaster; I wonder if any party since WWII has been in as bad a political position. Why would they want his continued leadership after he leaves office?
I won't wade into the debate about Obama's future, and will point out that I think the USA's effective two-party system is pretty busted, but yeah -- the USA has a pretty polar political past.
In 2008 they did not have a 'supermajority', usually interpreted to mean a veto-proof or filibuster-proof majority, in any house of Congress.
Also, today Republicans control both houses and the Governer's seat in approx. 33% of states.
Finally, the Dems can't win in some states due to gerrymandering and voting laws that prevent even a majority of Democratic votes from winning the election.
I'm not saying the Democrats weren't roundly drubbed in the last election, just refuting the belief that this might be the worst position a political party has been in since WW2. I hadn't thought of the state legislature, however! That's a good point.
The President is the head of the party; the DNC traditionally is run by his people AFAIK.