Here’s a good article examining the question, “Did Obama campaign on the public option?“
The short answer: No, Obama did not campaign on the public option. As a matter of fact, the Senate bill is pretty close to the plans he outlined.
However, he did campaign against a mandate, and he has apparently broken his promise on that. Ironically, it was Hillary Clinton’s position that there should be a mandate, and her plan was seen at the time as being more liberal than Obama’s. Irony, indeed.