He had just a couple of months of full Democratic control. Due to Al Franken not being seated right away, Robert Byrd being ill, and Ted Kennedy dying, the Democrats didn't have a supermajority until September of 2009. They then lost that supermajority in February 2010 when Scott Brown was sworn in.

I do agree that Obama tended to negotiate badly by compromising before it was even needed, but that "two years of full Democratic control" thing gets repeated so often, and it's annoyingly wrong.

Joe Lieberman threatened to filibuster any bill that had a public option. We wouldn't have had the votes to pass single payer, even when the Democrats controlled both the House and the Senate.

The Democrats went into the debate compromising with moderates within its own caucus. Joe Lieberman threatened to filibuster if a public option was added to the bill and effectively killed any chance of passing some form of HR 676 (originally introduced by Democrats in 2003, it was floated around early in the healthcare debates of 2009). So the Senate began working on a Republican plan that was introduced in Massachusetts under Mitt Romney. However Mitch McConnel convinced his caucus to not support the bill in any way and succeeded in stopping moderate Republicans from breaking rank.

This debate went on like that for a good while, with Democrats negotiating to keep moderates like Ben Nelson (Cornhusker Kickback, if anyone remembers) and Joe Lieberman from defecting. The Democrats were then dealt a blow by the death of Ted Kennedy and subsequent election of Republican Scott Brown to his seat in the Senate. With Brown's swearing in, the Democrats' caucus would have lost the filibuster-proof majority it enjoyed.

I just want to point out that a long debate was expected, and it would have likely gone on for another year had Kennedy's seat not been won by Scott Brown. The Senate's bill, which became the ACA, had to be the one implemented otherwise the Democrats would not have succeeded at any version of healthcare reform. Obama's '"compromise" position' was to encourage a bill that was not single-payer and could keep Blue Dogs on board.

I mean what should he have done? Kneecap Democrats who didn't fall in line?

Are you kidding? Harry Reid had to resort to procedural maneuvers to get the ACA passed – single payer would have been laughed out of the room.

Obama never had full Democratic control of the Senate.

Lieberman caucused with the Senate Democrats. He had lost his Democratic primary and ran+won as an independent. In fact, he'd endorsed McCain in 2008 (after Obama campaigned for him in 2006).

Lieberman had and used a line item veto over everything that was passed by the Democrats because the Republicans uniformly opposed anything that was proposed. It took a supermajority to pass the ACA and it only barely passed because of Republican opposition.