Politically I think it puts congressional Repubs in a tight spot. They can no longer afford to take the approach of thwarting Obama at all costs as it will probably be taken out on them in the 2014 elections and if Repubs lose to many seats Boehner and McConnell will risk losing theirs.
If Romney wins, I wonder what Republicans reaction will be if Democrats vow that they will oppose any Republican legislation or compromise on the basis of making Romney a one term President. If Romney wins Boehner's and McConnells ploy sets a horrible precedent for the nation and I have no doubt that there would be pay back by the Dems. This would not be good for the country. If Obama wins then their ploy will have obviously failed. What then?