Interesting, but your observation about Romney is an opinion...not a fact.
Of course it's an opinion. So is your assumption that Romney will reverse the mandate. But my opinion is based on his record, not on his campaign promises. It's also my opinion that we would not now be saddled with a national mandate if Romney hadn't paved the way in Massachusetts. The Republicans have utterly betrayed us by nominating him.
As to a third party vote contributing to an Obama victory...that is an absolute fact if the alternative is a Romney vote.
Uh.. nope. Wrong againg. If someone pointed a gun at my headed and made vote for one or the other of these asshats - I'd probably vote for Obama. So, by your logic you'd count my third party vote as "contributing to Romney victory". You're welcome.
Fortunately, they're not yet forcing us to vote for only Dems Or Rethugs, though I'm sure if Congress passed such a law Roberts would gleefully sign off on it.