Brendan Nyhan writes: “people are missing the forest for the trees in focusing on swing states, swing demos, etc. Large deviations from expected outcomes are likely to get pushed back toward fundamentals by the campaign – in this case, GOP and GOP-leaning independent women returning to Romney who are currently saying they don’t support him…”
Indeed, there’s a distinction between the electoral value of states—changes in opinion matter in swing states but not elsewhere—and the informational value of state opinions. Because of uniform partisan swing, we can learn (almost) as much about the election by studying swings in NY, Tex, and Calif, as by studying swings in Florida, Ohio, and Pennsylvania.