Without falling into the "Obama should do X" trap and at the risk of joining the cacophony of theories about the recent polls, I think it's pretty clear why the president's numbers are sagging.
While Americans tend to say to pollsters that they're sick of partisan bickering and the like, they actually kind of dig it from the perspective of wanting someone -- anyone -- to stand up and take strong leadership role. (Americans, despite what they say, also like fighting and competitions. See also the ratings of various reality shows.)
And on healthcare reform we're essentially being told, and thousands per day are experiencing first hand with great pain, the life and death nature of healthcare reform. Yet we're also told that such life and death matters can be compromised, and that compromise ought to be negotiated with a group of politicians who want to crush reform. In other words: here's the life-saving solution, but the solution needs to be weakened for some reason.
If a patient is having a massive heart attack, this is not unlike negotiating away one of the defib paddles. Well, maybe one paddle will do the trick because Dr. Wingnut McGooper doesn't agree that the patient is dying and, in fact, thinks saving the patient's life is a secret plot to kill the patient.
It's absurd and it has to stop. Now.
This is a matter of life and death. The equivalent of 9/11 casualties every two months due to our broken system. No more compromise. No more bipartisanship porn. Save this patient.
Adding... Another example of what Americans say to pollsters and what they actually do is illustrated by how few congressional seats actually change hands during an average election. Americans tell pollsters that they largely disapprove of Congress and that everyone should be replaced, but when it comes time to vote, we usually vote for incumbents.