It is certainly not breaking news that Sarah Palin is the darling of the most extreme fringe of the Republican Party, but here's yet another data point on it: she's by far the most popular potential 2012 candidate with voters who disapprove of Barack Obama and already want to impeach him. 86% of voters who fit that description have a favorable opinion of Palin to 62% for Mike Huckabee and 49% for Mitt Romney. That's a much wider popularity gap than exists among all Republicans, 73% of whom view Palin favorably to 57% for Huckabee and 51% for Romney. By...