According to Gallup, the GOP has now opened up a six-point lead over Democrats when voters are asked to state a generic party preference. As recently as last month, Democrats were leading by a point. (Though Republicans support is notoriously under measured in Gallup’s generic ballot .) Gallup says the Republican lead is the result of Democrats bleeding support:
Two structural changes in the data help explain the shift. First, while the percentage of registered voters identifying as Republicans has been consistent over the past several weeks, during the last week there was a decline in the percentage of voters identifying as Democrats and an increase in independent identifiers.