An analysis of Pew Research Center surveys conducted in late February and March finds the two Democratic candidates, Sens. Hillary Clinton and Barack Obama, running equally well against Sen. John McCain among voters in the big swing states of Florida, Ohio, Michigan and Pennsylvania; Obama led McCain 52% to 40% among a representative sample of voters living in these states, while Clinton bested McCain by a statistically comparable 51%-to-42% margin. Electability will be an important issue in the wooing of superdelegates by the two candidates, but the polling thus far suggests that neither candidate has a demonstrable advantage in this respect on the basis of where and among whom each candidate ran particularly well in the primaries. Read More

Russell Heimlich  is a former web developer at Pew Research Center.