“Gee, Obamugabe must have had a good polling day to jump from -16 to -12 that quickly.”
For some reason, this “underwater” metric is highly volatile day to day. I don’t put much stock in it. A 7 day rolling average would be more helpful.
Regarding the jump from -16% to-12%, don’t forget that hard core lefties often voice “strongly dissapprove” because Obama is too moderate in their opinion. The snarky debate posture could have moved them.