Except no other non-Obama candidate consistently sniffs 50%+ in any series of significant polling data, so it's entirely irrelevant. And this is the absolute rock bottom low point for the administration with the BP spill, no benefits from healthcare coming until later this year, and the economy taking a very temporary dive due to European debt issues. The spill will of course go away eventually and the economy will improve, so it really won't be difficult for Obama to maintain around 50%. He blew out the most liberal guy the Repubs could get in 08, won't be terribly surprising if he holds on for a 2nd term, and the smart money is on exactly that. Plus, again, we know who is a better speaker, campaigner, and disciplined debater, if you in particular didn't see it between the two in 08. You have to absolutely bank on a complete unknown, that's just the reality.
So far, Obama has nothing that the public sees as positive to run on.
He will try to take credit for an economic turnaround by 2012 but investing $225K per new job that in the end turns out to be mostly temporary Census employment is a no go right from the start.
He is spending huge amounts in Afghanistan as well as sending lots of soldiers, but what happens if they are pulled out without a decisive change there?
Bin Laden and pals are now being identified as resident in Sabzevar, Iran for the past five years. Blame Bush? Obama is the president now. What is he going to do about it and those nuclear weapons development sites?
Obama has been bashing Israel. The Israelis are under a lot of pressure these days and a lot of American voters still support them. What happens if Obama hangs them out to dry?
Obama still intends to fundamentally transform America and a lot of people want the country to stay American. Expect a continuing backlash.
The Gulf oil spill is Obama's nightmare. It will affect Gulf state economies for a long time. If Obama moves to take over BP assets, he will destroy relations with the UK as BP is that country's largest company. If Obama stops BP from paying dividends he will materially affect the pensions of most of the UK and many here in the US as well. It is a lose-lose scenario that casts him and his advocacy of an all powerful government down the toilet.
He won the last election by running against Bush. Who can he tar as Bush this time around? I read the Dems will try to run against Bush in the 2010 elections, let's see how far that gets them.
As far as contenders go, I believe we already know of the likely nominee, we just don't know who it is going to be. My guess it will not be one of the people most mentioned unless it is Romney in response to a worsening economic situation.