It's social issues. Subrbanites are becoming more Dem over social issues.
The thing is, Romney was about the best Republican candidate imaginable for the Anne Arundel County demographic, and he still lost ground there in absolute terms.
He wasn't. He might have been, conceivably, if he'd won the Republican nomination on his record as a Governor rather than on his warchest, and if he'd just come across as standing for anything period, but then he couldn't have won the Republican nomination that way.