This Gallup report on Wednesday morning caused a few Democrats to lose their donuts. It found almost one out of three (28%) of Clinton supporters say they would support McCain if Obama were the nominee. Let’s call them the Benedict Arnold Caucus. But who are these potential partisan turncoats? Are their answers to pollsters mere grousing or permanent pique? And have we seen this kind of behavior in previous elections? Some believe the traitor talk is overblown. Yesterday Gallup followed up with a more detailed analysis demonstrating Democratic leaning independents (39%) and self-identified Democratic conservatives (38%) were the primary culprits, saying they would vote for McCain if Obama were the nominee. Blacks (15%) and self-identified liberal Clinton supporters (18%) were the least likely to defect, the report observes. These numbers are consistent with this piece by David Paul Kuhn in yesterday’s Politico, suggesting the McCain campaign is considering a major offensive to attract Reagan Democrats back to the GOP if Obama were to win the nomination. The Gallup report also suggests the Benedict Arnold contingent is bigger within team Clinton. The poll finds that, on average, Obama supporters across various subgroups are less apt to defect than the Clinton partisans. According to Gallup,