That Obama's approval rating falls into the high thirties (where he would almost certainly lose re-election) or rises into the high forties (where he could easily win -- much like George W. Bush in 2004)?
Rick Perry loses his temper with Ron Paul, or Rick Perry dozes off during the last half hour?
Hispanic voters or Jewish voters?
Congressional Republicans having a veto over his economic policies, or the financial turmoil in Europe -- which he has no control over.
Neko Case or Jenny Lewis?
Rick Santorum or Jon Huntsman?