Briefly: Romney's display of idiocy won't change the minds of too many voters. Those who believe Obama is on the side of the terrorists weren't going to vote for him anyway; there will be some who are sufficiently disgusted as to decide to vote for Obama.
But what Romney really lost was the Village and the press. It has become impossible for the pundit crowd to pretend any longer that this man should be allowed anywhere near the White House.
Without the protective top cover of the "non-partisan" punditry, Romney will have a much more difficult time advancing his lies. And without lies he's got nothing.
See also Demi Moaned's take on this same blog.