He is hedging. Basically he’s saying, based on the historical party identification and turn out, Democrats have 2-4% advantage, so Obama might win. However, we have many people who are on the fence. Historically,they break for the non-incumbent, so Romney might win. Either way, he’ll keep the status of most accurate pollster.
Like 1994, and 2010, the great conservative and even moderate American sleeping giant will turnout and MAKE HISTORY. This WILL NOT BE a "normal election". They (we) are deeply fearful for our nation and will turn out and vote.