This was Romney's strategy for the third debate, and I think it went pretty well. This is the strategy of a campaigner who thinks he is winning and wants to maintain his trajectory. Romney avoided several opportunities to "zing" Obama, not least on Libya. Conservatives were drooling for Romney to deliver a rhetorical uppercut and KO the President, but Romney played it safe.
I have no doubt that Romney's calm, stable vibe was a conscious strategy. Look like a commander-in-chief; don't say anything dumb; don't act like a warmonger. I think Romney accomplished these goals. Did he set the bar high enough for himself? I guess we'll find out.
President Obama, on the other hand, really wanted to nail Romney as inexperienced on foreign policy, "reckless", and "all over the map" erratic. Obama needed people to see Romney as an unacceptable, ignorant, dangerous commander-in-chief. I don't think he accomplished this. The President said most of the right policy talking points, but I think his attacks on Romney fell flat because of the Governor's calm demeanor and steady responses. The "horses and bayonets" snark might work in the Oval Office against your subordinates, but I think Obama will rue that comment in the following days.
(Romney didn't make up the "number of ships" metric he used -- that's now the Navy measures itself and makes its requests. The numbers Romney quoted came from the Navy. What's more, our infantry still uses bayonets in combat and we've got millions of them; we even used horses in Iraq and Afghanistan, though certainly not as many as 100 years ago.)
So, who won? The President came on strong. However, I think that Romney achieved his goals and Obama did not. It's a mistake to assume that both campaigns are aiming at the same target in each debate -- they're not. Each candidate uses each debate to achieve a strategic goal, not just to "win" on rhetorical points. So in that light, I'm going to call the debate a win for Romney.