Not "Obama Only" ballots, but Straight Democrat ballots.
That explains the results in Wisconsin and Pennsylvania where every statewide race down the line went for the Democrats. In previous years, in both states, statewide races are typically split between the parties.
You can get away with this if those ballots are reserved for "safe" districts/wards where nobody will fuss and where the House race is not affected.
This fraud was conducted to ensure Obamacare would remain in place, even if Obama somehow lost as the Senate would remain in Dem hands.
actually in Wisconsin all the state races went GOP but Senate and pres went democrat, saw Gov walker discuss this on election night
lazy ballot fraudsters in Wis didn’t bother with local races