The 50-plus Democrats considered vulnerable by The Cook Political Report have voted with Republicans about 20 percent of the time on those 15 votes. Some of the members didn’t desert the party on any of the major votes.
The votes include last week’s climate change bill, the stimulus package, President Obama’s budget and other votes like an amendment to cut off funding for the closure of Guantánamo Bay prison.
The defection rate has been much higher in the subset of 10 Democrats whose districts went for GOP presidential nominee John McCain (R-Ariz.) by double digits — 45 percent. All but one voted with Republicans on the energy bill and all but two voted to keep Guantánamo open.