"Tea Party" is a reference to the Boston Tea Party, in which "Tea" stood for tea.
We are puzzled to learn that Rick Perry's success in a South Carolina Tea Party poll is being credited to (or blamed on) a high incidence of Christian self-identification in that state. Puzzled, because we were earlier informed that the ever-spooky religious right was but a fringe movement that should be shoved aside to make room for the overwhelming numbers of religiously-indifferent "TEA Party" voters obsessed with social issues.
Yet Perry's success doesn't seem to be viewed as a refutation of the theory, apparently because of unsubstantiated claims (from Wikipedia) that South Carolingians are more religious than denizens of other states.