Among independents, Romney’s unfavorable rating now tops 50 percent — albeit by a single point — a first in Post-ABC polling back to 2006. Just two weeks ago, more independents had favorable than unfavorable views of Romney; now, it’s 2 to 1 negative.

Romney’s losses since a Post-ABC poll conducted between the Iowa caucuses and the New Hampshire primary are not limited to independents. The number of Democrats viewing him unfavorably is up 10 percentage points, and among his fellow Republicans, negative ratings have jumped from 18 to 32 percent. (Prior to his Iowa performance, Romney’s unfavorable number had been higher than 18, but hadn’t been in the 30s among Republicans since early 2008.)…

One reason Romney has been outperforming Gingrich in hypothetical match-ups against President Obama is due to independents. Now, both main Republicans are at a disadvantage.