Now why would this be?
I suggest that it is because limiting him to how much internal revenue he can raise and how he can use these dollars would be detrimental to his campaign in 2012. The $timulus was a massive pay-off and payout to his biggest liberal constituencies: Wall Street cronies and Union thugs. I've picked up on some chatter that he plans to raise $1B dollars of campaign funds for his 2012 campaign but let's be clear that too much is never enough for this guy and when you are suffering the disapproval ratings of this presidency you have to be concerned that these campaign funds in the hundreds of millions will not be enough to drown out a bad public record utterly lacking in popular accomplishment, not to mention the genuine ideas coming from one's opponents. He's a lot of things but he's not a gambler. Rather than leave it up to voters, all of whom (conservative and liberal) he despises and disrespects, he'd rather buy the necessary votes to secure reelection.
With a limit to the debt ceiling there is an ever increasing unlikelihood of another slush fund like the $timulus. His most loyal constituents, government employees will be made to sacrifice and suffer and his most scorned political enemies, the contributing class of free-market American workers will not be punished with new tax increases (as if we haven't suffered enough already in this economy).
Obama also gets the benefit of creating another crisis that he and his Chicago-land thugs have all too openly admitted they look to exploit for political gain.
But this is how Obama has painted himself into his own corner. On one side, in creating another crisis he, at the very least, has co-ownership and responsibility to resolve the crisis. On another side, he will have to choose whether to limit himself from his resources (our tax dollars) and his political tactics of bribery and coercion (pundits can paint it up with whatever thesaurus they want to use, this is what we call these things in the middle of the country). On all other fronts Obama is facing a very public set of decisions less than 18 months before the election -- voting present, his preference, is not an option.
So again, Republicans have made it well known what the rules are in this negotiation. They have told the President and the Democrats what is on the table and what is not on the table. Anyone in business knows that until you make those determinations you aren't really negotiating, you're just having a conversation.
According to all the experts, the clock is ticking . . .
. . . your move, Mr. President.