I think what many of my "progressive" friends are missing here is that politics is the art of the possible. For all its problems the health care bill got past cloture 60-40. With a public option or a medicare buy in provision it would be dead.
What is the point of introducing legislation that is going to fail? Had Obama tried to ram something down the Senate's throat like Clinton tried he would have failed. There are a good number of Dems from places like Ohio, Montana, etc., who are not as far to the left as some might like, and their constituents are probably to the right of them. Lets see what the joint house-senate bill looks like, before we go off declaring Obama to be the next Jimmy Carter.