Obama loses by not pushing Mitt into a mistake, or by hitting him with a problem Romney will have to clean up tomorrow.
Could Mitt have done more, particularly on Libya? Sure. But he didn’t want to score cheap points on Obama. He wanted to win points with the (dwindling number of) viewers at home.
The three-question test for every candidate is: Do they like you, do they trust you, do they think you can do the job. Mitt already owned the “competence” issue, and the “trust” issue is what it is. Mitt Romney seemed determined he would be the most likable guy on stage.
President Obama’s snarky sniping (“We have these things called aircraft carriers”) let him achieve that goal.
The win goes to Mitt.