See this U.S. New & World Report analysis by Michael Barone, arguably the best journalistic analyst of modern American politics. Examining demographics of the next few big states to vote - OH, PA, TX, WI - Barone concludes that two of these races definitely favor Clinton: OH and PA. WI he believes will probably go to Obama, and TX is up for grabs.
He bases his conclusions on the relatively small number of black voters in all of these states and of educated white Democratic voters in all except WI. Barone completely ignores the so-called "momentum" factor about which other pundits are waxing rhapsodic. I suspect he ignores it because it has been a noticeably unreliable predictor this year.
