2016 with incumbent Romney and Dem contested convention

[odieluck]

Say Romney wins in 2012 and manages to pass a good deal of his agenda through, and the GOP manages to narrowly hold the house in 2014 and make slight gains in the senate. Now in addition to this, say Bernie manages to go all the way to the convention and loses only due to superdelegates. How big of a rift does this cause in the Democratic primary and how big of a margin is Romney reelected by? Also, does Jill Stein's vote increase significantly as a protest if the primary is seen by more people as 'stolen' from Bernie?

[wnwnwn]

I think most of the party would unite agaisnt Romney.

[odieluck]

Sure, but do you think there would be enough defections compared to OTL to make a substantial difference?