American's don't like to give up on their president. We want the president to succeed in a general way because we know if he fails the nation is harmed to some extent. In many respects Barack Obama is on a path blazed by James Earl Carter over three decades ago. More Americans "liked" Carter than thought he was doing a good job as President. That fact likely played a heavy part in keeping Carter's polling position respectable throughout 1980.
Warren Mitofsky of CBS News made an interesting study of polling during that campaign. Intuitively I would assume that some Americans wait until fairly late in the game to admit (even to themselves) that they are not voting to re-elect a president, and Mitofsky's research bears that out. For instance Ronald Reagan got between 41% and 46% in every poll over the last two weeks of the 1980 campaign but received 51% on election day. Even that late in the game there was a slice of the electorate who were hesitant to admit they were abandoning Jimmy Carter. On the other hand in the twelve polls that showed 5% or less "undecided" voters over those final two weeks, Carter received between 40% and 45% or an average of 42%, just 1% more than where he ended up.
I think its safe to conclude that roughly 70 % of all voters know beyond all doubt whom they will support in November. Another 15 % or so are nearly as set with only a cataclysmic event likely to sway them. Under this scenario both Romney and Obama have between 40% and 45% support today. Whether its Obama 44-41 or Romney 43-42 or tied at 41 is largely irrelevant.
This election (absent some incredible gaffe by Romney) will be about Barack Obama. It will be his report card on the past four years. Currently in the RCP polling average Obama is stuck at 45.7%. That is an awful number and its getting worse. Of the seven polls RCP is currently using only one has Obama above 47% and that is a two week old CNN poll of registered voters. The last three days of May is ancient history and a poll that old is only barely more relevant than the Lincoln-Douglas debates. The most recent is the Rasmussen Tracking Poll of Likely Voters that shows Romney up 48-44. The last five polls based on end dates show Obama at 47-46-46-45-44 which is a scary trend-line for Democrats.
I think it is not unreasonable to conclude that Barack Obama is teetering on the edge of an electoral abyss. His numbers are stuck well below where they have to be to have a chance to win. All Mitt Romney needs to do is stay close or slightly ahead and those now claiming to be undecided will break his way very late. If I'm correct that 2012 is playing out much as 1980 did, and absent a horrific event that totally changes the game, Obama could well lose by an 8 to 10 point margin.