Democratic Defection Rates

According to Gallup's latest survey, 28% of Clinton supporters would vote for John McCain over Barack Obama, and 19% of Obama supporters would chose McCain over Clinton.

“The data suggest that the continuing and sometimes fractious Democratic nomination fight could have a negative impact for the Democratic Party in next November's election. A not insignificant percentage of both Obama and Clinton supporters currently say they would vote for McCain if he ends up running against the candidate they do not support.”

I wonder whether the different demographic coalitions that the candidates are putting together are in some ways responsible -- whether, for example, white men have higher defection rates than women.