The President doesn't need to be at 55% approval to win a solid victory. If 52% is his real number -- and I suspect it's a bit lower than that, because most other pollsters have it in the high forties -- he'll win pretty easily.
The Rasmussen JA numbers are high compared to other polls and the horse race numbers low, so 55% would be a good number to aim at, which would translate to 51% or something like that for the other polls.