It's not an 'anti-incumbent' mood. It's an anti-Socialist mood and we no longer give a fig what party label the Socialist wears.
L
Incumbent=socialist.
Jonah never says it’s an anti-incumbment mood, those are the article poster’s words.
Jonah’s point is that the Tea Party is not a pawn of the GOP as evidenced by their dumping of Benett (pro-tarp,pro-amnesty,pro-individual mandate, etc.)