A certain number of votes hang on each issue, true. But Romney's open contempt for "social conservatism" (i.e. conservatism) lost the single most critical voting block that any Republican needs to win. Just losing this one group cost him, cost us, the United States, quite possibly.
Let’s see - we also have scorched-earth during the primaries. Gross neglect of any likely GOP unregistered voter registration drive like that Rove built in 2004. Unwillingness to keep hammering Obama after the first debate. The ORCA debacle. And just the plain fact that he was the worst possible candidate to run against Obamacare and the Dems being in bed with Wall Street. Plus a stunning inability to connect to middle class voters.